tag:blogger.com,1999:blog-57614899228217390962024-03-13T14:30:07.830+11:00A Perfectly Formed PuddleAndyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.comBlogger340125tag:blogger.com,1999:blog-5761489922821739096.post-35928752367244273102016-07-08T11:10:00.000+10:002016-07-08T12:43:50.419+10:00SUSY 2016 Liveblog: Day Five Session Two<div dir="ltr" style="text-align: left;" trbidi="on">
It's already the last session of the conference, a mixed selection of talks.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195567/attachments/1306048/1951962/SUSY16_teb.pdf">11:00 am</a>: <i>Belle II Physics and Construction Status</i>, Tom Browder</b><br />
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Belle II is the first new collider since the LHC turned on. Working, of course, on the intensity rather than the energy frontier.<br />
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A line of attack of interest to me is dark photons. It's good to see efforts being made to address invisibly decaying dark photons. Of course, that's not that new (I used projected limits in a paper several years ago) but that was based on what theorists thought could be done.<br />
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B physics is a major planned program. Leptonic decays B to τν are a good avenue to probe the Higgs sector, in particular the presence of charged Higgs. Amusing difference between theorists and experimentalists. Xerxes Tata stated that type-III 2HDM is "FCNC hell"; for an experimentalist, with so many signals it's FCNC heaven!<br />
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Search signal is challenging: B decays to charged track plus nothing. But pair produce Bs, which helps with reconstruction; only really possible at an e+e- collider. Still, no observation yet from Belle/BaBar, only observation. But prospective limits are still much, much better than direct searches at the LHC are likely to be.<br />
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B to D decays important as we've seen some anomalies there. Indeed, BaBar paper from 2012 saw clear discrepancy with SM while inconsistent with any type-II 2HDM (tau fraction of decays for D and D* final states). Current status of combined results is at 3.9σ from the SM. Belle II can shrink the uncertainties by a factor of 4 to 5, which should resolve things one way or the other.<br />
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Asymmetries in B to Kll decays are another current interesting area. As discussed yesterday, there is a discrepancy in the kinematic distributions. Worth emphasising that the discrepancy lies in one of two parity-violating observables. (There is a very mild tension in the other PV observable, the forward-backward asymmetry.)<br />
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Why should we see a discrepancy here? Well, one think is that the loops generating this process in the SM involve the heavy particles (W, Z, t). Also, interference could be important: linear effect.<br />
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Severable observables are seeing 4+ sigma discrepancies from the SM. So what's the problem? There are some theoretical issues with calculating the SM predictions. There's some dependence on hadronic form factors that should be checked on the lattice. Checks using HQET also continue to show need for NP. But still need more data and theory to trust everything.<br />
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Some details on Belle II experiment/detector. Most important point: first collisions anticipated in December 2017, with the physics run to begin late 2018.<br />
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<i>Questions</i><br />
Complementarity with direct searches interesting. Note also probing SUSY parameter space, worth presenting results to show that. <br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195574/attachments/1306025/1951960/2016-750GeV.pdf">11:30 am</a>: <i>The 750 GeV Anomaly</i>, Alessandro Strumia</b><br />
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This looks like the talk he gave at Moriond; the slides are more optimistic than I expected. Though the spoken part is not so much ...<br />
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Diphoton has got us excited because we don't have anything else to play with. It cannot be systematics; experimentally and theoretically very clean. So either a statistical fluctuation or a new particle.<br />
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Discussions of the expected stuff. Limits include invisible channels. The simple model with new fermions/scalars in the loops runs into problems with perturbativity. Including DM might make things easier because you can hide stuff in invisible decays of the putative resonance.<br />
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Composite models based on quark-like bound states have the problem that you'd expect a colour octet near 750 GeV. Other models which include some more general composite dynamics; best case is to make the resonance composite but have an elementary Higgs. (I don't know that I agree with that.)<br />
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Ultimately the theory statement is that we need some extra charged states. Why are they light? There are various possibilities; SUSY, unification, scale invariance or extended gauge groups. Ultimately it might (if we are lucky) tell us where to go.<br />
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Looking ahead, we have to find this thing in other final states; measure its spin; and identify the production mechanism. Measuring the couplings is important; interference effects could be important. Double production could also be very important should the state be strongly coupled. Any extra fermions or scalars should also be looked for.<br />
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Final slide: told not to talk about rumours, but essentially tells us what we know anyway. Including plots hinting at the deficit that has been reported in new data.<br />
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<b>12:00 pm: <i>Outlook</i>, Hitoshi Muryama </b><br />
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I can forgive the absence of slides for the summary talk.<br />
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We haven't found what we'd hoped. So why should we still consider SUSY? Usual list of motivations. But why not? Flavour, CP problems; gravitino overproduction; proton decay; Higgs mass.<br />
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The Higgs boson is the only spin 0 particle in the SM. It lacks context but does the most important job in the theory. SUSY offers the "explanation" of many scalar bosons, of which only one happens to gain a tachyonic mass. But other explanations (composites or gauge-Higgs unification) do exist.<br />
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Higgs mass is peculiar: bad for theorists but good for experimentalists. Theorists suffer from the fact that no clear evidence; SM potential metastable, not quite consistent with SUSY, etc. But lots of experimental channels to search. This at least gives us a potentially powerful probe.<br />
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Divergence of masses has been seen before. In classical electrodynamics, the quantum corrections to the mass from its own field is of the order of GeV. There would need to be a tuning of at least 0.01% to get the correct mass. However, quantum mechanics and the associated doubling of states (antiparticles) reduces the divergence from linear to logarithmic. In this sense, the SUSY explanation of the Higgs mass is the same.<br />
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Another successful use of naturalness comes from inflation; why is the Universe so big, flat and entropic? These theoretical problems were explained by inflation.<br />
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Cosmology also gives a time when things where problematic; before Cobe, people were worried about the non-observation of the CMB anisotropy. Part of the problem is that the CMB quadropole happens to be about 1% tuned smaller than the best-fit curve, which delayed the discovery. Perhaps we are in the same position right now.<br />
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Upper bounds on sparticles? Mini-split arguments: DM and gauge unification. unification puts sparticles below 100 TeV, DM requires some states at TeV. Similarly the Higgs mass points to moderately heavy stops. Even this sort of situation would reduce the tuning from that in the SM to about 10<sup>-4</sup>.<br />
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No sign of NP means natural and simple models are excluded. Choice between theory complexity or fine tuning model. Can perhaps get better SUSY models if we abandon (say) WIMP DM or unification. Discussion of SIMPs, and their detection prospects using hidden photons. General problem is that we have almost no idea what the DM mass should be.<br />
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Effective operator analysis of BSM physics. Notable that while first looked at in 1980 by Weinberg, complete set of d = 6 operators only constructed three years ago. But already we can automate this. Possible direction for flavour physics?<br />
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Susy in the future... We shouldn't panic just yet. We can still find things and still talk about it for some time!<br />
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<b>SUSY 2017 Announcement</b><br />
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Will be held at TIFR in Mumbai in December 2017.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com1tag:blogger.com,1999:blog-5761489922821739096.post-20463931429879878392016-07-08T09:33:00.003+10:002016-07-08T11:04:08.367+10:00SUSY 2016 Liveblog: Day Five Session One<div dir="ltr" style="text-align: left;" trbidi="on">
One thing that's clear in the negative category for this conference is the lack of power outlets. I'll discuss the talks I had to see yesterday without power in the next few days. Instead, we move on to the last day of talks, which is another half-day of plenaries. Last night was the conference banquet, and I didn't get back to my hotel room till after 1am, so I'm a little surprised I've only missed one talk.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195564/attachments/1306033/1951927/SUSY2016_Huang.pdf">9:00 am</a>: <i>Scattering Amplitudes</i>, Yu-tin Huang</b><br />
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This is the talk I (mostly) missed. Which is a bit of a shame, as these ideas about more efficient methods of calculation are interesting, even if they can't be applied to any real theory yet. Apparently (from the conclusion), what makes the theories where these ideas can be applied is their soft properties: universal behaviour as momenta go to zero.<br />
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<i>Questions</i><br />
What does perturbative completion with gravity say about UV gravity? Perturbative completeness means string theory is the only current working possibility.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195565/attachments/1305384/1950626/MJRM_SUSY_16.pdf">9:30 am</a>: <i>Baryogenesis</i>, M.J. Ramsey-Musolf</b><br />
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The baryogenesis problem: one number we cannot explain in the SM (baryon asymmetry). But, the number of BSM explanations is almost unbound. If we're going to look to experiment to resolve which idea is correct, it helps to know the energy scale associated with each mechanism. High-scale ideas like leptogenesis are obviously harder to test, but not entirely impossible.<br />
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However, the focus in this talk is on a low-scale model: EW baryogenesis, where ΔB is generated at the same time as EWSB. This demands a first-order phase transition, which is not the case for the SM Higgs parameters. New scalars are thus a necessary condition.<br />
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The classical example in recent years for these scalars are light stops. When they are below about 160 GeV, a first order PT occurs. However, for baryogenesis we need even lighter stops, around 100 GeV, for the transition to be sufficiently strong. These are in severe tension with the LHC null searches. There are also constraints from Higgs measurements.<br />
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So naturally people consider different alternatives. A simple but interesting possibility is to consider a standard scalar Higgs portal. These show up in many theories but a single real scalar is a computable toy model. Several feasible scenarios (pre-LHC). When the singlet is heavy, the search channel is resonant diHiggs production; this might be discoverable with 100 fb<sup>-1</sup>. However, to fully probe this parameter space would need a 100 TeV machine.<br />
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When the singlet cannot decay to the Higgs, then the search strategy is based on precision measurements of the Higgs couplings. The states are similar in mass and so mix fairly strongly. Most of the parameter space can be tested with a linear Higgs factory. When the Higgs decays to the singlet, there's some question what can or cannot be probed.<br />
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Moving from a singlet to an EW multiplet as the new scalar, you get the interesting possibility of two-step transitions. First the new scalar gets a VEV, then you transition to a phase where only the Higgs VEV is non-zero. The presence of charged partners in the new scalar multiplet means that the Higgs diphoton width is a natural place to look.<br />
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A strong 1st order PT is not the only requirement, of course. Sufficient CPV is required, and this runs into problems from EDMs. A rough bound, if EDMs are generated at one loop, is that the new states are either multi-TeV; or, if they are at the EW scale, the CP phase is small (0.01). Though (no details due to time) apparently this does not prevent EWBG.<br />
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<i>Questions</i><br />
What of Affleck-Dine baryogenesis in SUSY? Possible, to be sure; just wanted to focus on rich EWBG pheno.<br />
Flavoured BG (from skipped slide)? Generation through flavour-violating lepton couplings. Suppresses EDMs. Probed by Higgs couplings to τs.<br />
Two-step scenario excluded for same reasons as SM EWBG? No, due to lower temperature of second transition; never reactivate sphalerons.<br />
What about computation of baryon asymmetry? Some details.<br />
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<b>10:00 am: <i>Exotic Searches at ATLAS and CMS</i>, Shahram Rahatlou</b><br />
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Another speaker who feels no need to upload their slides. Given that this is an experimental summary talk, I'm not sure if I should even bother annotating this talk; it's just going to be a lot of null searches that I won't be able to get all the details for.<br />
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General search strategy: do the easy stuff first. Hence, look for resonances first. Do the easy resonances (dileptons, diphotons, dijets) before harder ones (ditops, dibosons, mixed final states). New result: different flavour dileptons (eμ). No signal, of course.<br />
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Top partner searches recently added single partner production. Enhance mass reach at cost of some model-dependence in production.<br />
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Discussion on diphotons. (We have a whole talk on this later from Strumia.) Not too much new to say. He's being less pessimistic than the experimental speakers from the parallel sessions on Tuesday were, but I'll talk about that in a later plot. Main conclusion seems to be: despite the absurd amount of theoretical work, no one has suggested something the experimentalists <i>should</i> be doing that they aren't. Note that <i>Zγ</i>, which has to exist as well, shows no excess at 750 GeV.<br />
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Mono-X and similar DM searches. Greatly expand the final states searched for compared to run-I.<br />
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Long-lived objects difficult, so only one run-II result so far (heavy stable charged particles).<br />
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Conclusions: extensive search program, but only the most basic and simple theories have been probede so far. The next two years are critical; the happy ending is finding a new particle, which tells us what to do and might even justify an upgrade in the LHC energy. The sad direction is nothing and we have to focus on Higgs couplings.<br />
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<i>Questions</i><br />
Resonances searches should really include examinations of subtle interference effects. True, but this is not really a day-one strategy. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-33499189398677974822016-07-07T14:07:00.001+10:002016-07-08T09:33:45.862+10:00SUSY 2016 Liveblog: Day Four Session Three<div dir="ltr" style="text-align: left;" trbidi="on">
The first post-lunch parallel sesion, discussion of non-SUSY models. I don't come to SUSY to talk about SUSY :)<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2165200/attachments/1304417/1948795/hierarchy.pdf">2:00 pm</a>: <i>The Hierarchy Problem in Non-Supersymmetric Extended Models</i>, David Miller</b><br />
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Light Higgs is most easily accommodated with SUSY, but what if we don't find it?<br />
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Light Higgs also intriguing because of what it tells us about the SM vacuum stability. The quartic coupling runs to zero or below at the Planck scale. The quartic beta function also vanishing at this scale; not a fixed point and special for 125 GeV. Indeed, this was "predicted" in 2010 within a couple of GeV. The idea was <i>asymptotic safety</i>, with quantum gravity proposed as a way to tame the higher-order corrections. Unfortunately, their calculation was not fully gauge invariant, raising some problems.<br />
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Another interesting prediction from 1995 is the Multiple Moint Principle: that there is another vacuum at the Planck scale and degenerate with the EW vacuum. It was a prediction of the Higgs mass and a postdiction of the top mass (just after discovery). The original computation was at one-loop; improving to 3 loops is not such a good prediction, going for a Higgs mass around 128 GeV. (Still within three sigma of observation.) Note that there is an (obvious) dependence on the UV boundary condition, <i>e.g.</i> Planck/reduced Planck mass.<br />
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Can idea be implemented in a non-SUSY GUT? New fields will modify the running. Toy model: new complex scalar. Enforce stability at all scales. Kind of works, but extra quartic: should really obey similar boundary conditions, which makes things worse. Also consider 2HDM with similar conclusions.<br />
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Various planned efforts, <i>e.g.</i> postdiction of Higgs mass.<br />
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Bugger - I'm out of power and there aren't any convenient power outlets. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-35793044199406208622016-07-07T11:22:00.001+10:002016-07-07T14:00:05.851+10:00SUSY 2016 Liveblog: Day Four Session Two<div dir="ltr" style="text-align: left;" trbidi="on">
The second plenary session of the day looks at some deeper questions of theory.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195561/attachments/1305092/1950093/SUSY2016.pdf">11:00 am</a>: <i>Naturalness</i>, JoAnne Hewett</b><br />
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Naturalness told us to expect NP as soon as we turned the LHC on. We didn't see it, at run I or (so far) run II. What should we do? Panic? Hope the 750 GeV excess persists? Give in to anthropic arguments?<br />
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Let's panic (it's more fun).<br />
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How is naturalness defined? For concreteness, consider SUSY. There are several fine tuning measures that have been advanced: the traditional Guidice value based on variation of the Higgs VEV to input parameters; one based on large-logarithms; and one based on EW-scale inputs. Different choices lead to different answers, so there is a definite subjective element in what an individual scientist will consider the <i>true</i> fine-tuning.<br />
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Model building can give us further ideas. Consider the CMSSM. Pre-LHC, the best-fit values for the SUSY parameters were just beyond the limits: turn on the machine and see it. But now m<sub>0</sub> and M<sub>1/2</sub> are up at the TeV-scale, which most people will agree is in some tension with naturalness.<br />
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But of course, SUSY is not a single model. The pMSSM is in many respects just as valid a model, but the extra parameters will offer different phenomenology. A 10<sup>5</sup>-point scan of the parameter space finds points with gluinos and squarks down to a few hundred GeV still allowed by LHC data. This analysis was repeated and confirmed by ATLAS. We see several features in these lighter sparticle spectra: Compressed spectra (with little MET), Stealth SUSY (with complicated decays) and kinematic suppression. The 13 TeV results extend the exclusions but there remain many points with sub-TeV gluinos. Even with 3 ab<sup>-1</sup> of data, there will be a handful of points that survive.<br />
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However, focusing on a specific low-fine-tuning subset of pMSSM data, they will be excluded by the LHC with the full data set. Common feature of these models: suite of light and compressed EW gauginos, leading to a complex stop decay pattern that weakens constraints. This provides us with a guide for future developments in search techniques. A recent example is to look for charginos boosted by QCD ISR together with photon FSR (that tends to align with the MET).<br />
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Move on to discussion of RS models. I saw several of these points in Tom Rizzo's talk on Tuesday about explaining the 750 GeV excess using KK gravitons. Need to use large BLKTs to suppress couplings of KK gluon. But the general conclusion is that BLKTs are naturally expected, and extremely important for the KK phenomenology.<br />
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<i>Question</i><br />
Naturalness can be made rigourous in Bayesian statistics (up to priors).<br />
pMSSM requires throwing away (some of) the motivations for SUSY. Additionally, 10<sup>5</sup> points sounds too few (10<sup>8</sup> done by questioner John Ellis). How do fraction of points that survive compare to <i>e.g.</i> Bayesian analyses? Do not; there is no statistical power associated with these statements.<br />
750 GeV excess can be explained with radion, as Jack Gunion (asking the question) and I talked about at this conference.<br />
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<b>11:30 am: <i>Supersymmetry: to be or not to be?</i> Hermann Nicolai</b><br />
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Oh look, another speaker who didn't feel the need to upload their talk in advance.<br />
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"Take a more fundamentalist approach". Word choice; the SUSY = religion jokes are easy enough to make as it is.<br />
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Why SUSY? Start with Coleman-Mandula, which is where I started back as a grad student, so I'm feeling more sympathetic already.<br />
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Interesting point: positive cosmological constant (as appears to be realised in nature) is <i>not</i> consistent with SUSY!<br />
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Maximal rigid SUSY is N = 4; maximal supergravity is N = 8. These theories are essentially unique due to the restrictions of the SUSY algebra. However, people immediately realised that N = 1 SUSY is the unique theory with chiral fermions (and elementary gauge bosons). It is also motivated by string theory, and is the only theory we can hope to see at the LHC (check this).<br />
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A problem with SUSY since the beginning is how to break it. Ultimately, no completely compelling mechanism. Spontaneous breaking insufficient, hence the soft breaking usually adopted. Problem is worse in string theory. (Time-dependent cosmological backgrounds always break SUSY.)<br />
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What if the LHC does not find SUSY? Original SUSY model expected a 3 GeV photino! Opinion: should have seen (traces of) N = 1 SUSY at LEP. But then what? Other ideas for naturalness & DM that would not need SUSY. But more speculative idea: what is the fate of space-time SUSY in quantum gravity theories with emergent space and time?<br />
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Move on to maximal theories. As essentially unique, no freedom to fiddle with things which would apparently make them maximally testable. But connection to "more important" exceptional symmetries. For D < 3, these exceptional symmetries are infinite-dimensional. The theme seems to be that this makes things impossible to analyse...<br />
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I admit, I got a bit lost there.<br />
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Going back to N = 8 supergravity, could perhaps be finite (which would be bad for string theory). Odd coincidence: 56 fermions equals 3 x 16 + 8, which means ... what, exactly? Something about how we wouldn't expect any new fermions, but I don't follow why.<br />
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That said, I think this was probably the best this talk could have been; I'm not familiar with the technical details, but explaining them would have taken too long and been pointless for many people.<br />
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<b>12:00 pm: <i>Non-linear Supersymmetry</i>, Renata Kallosh</b><br />
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<i>Another</i> speaker who has not uploaded their talk.<br />
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Inflaton model where non-canonical kinetic term is motivated from SUSY Kahler potential.<br />
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Eventually got to some point, about supergravity with a positive cosmological constant. SUSY is realised non-linearly, such that a fermion transforms into a function of fermions (only). SUSY is spontaneously broken/non-linearly realised; equivalent to taking scalar particle to infinity. But I kind of lost interest with the first half of this talk and missed how it all fit together.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-9970795110382711002016-07-07T09:09:00.000+10:002016-07-07T11:26:06.790+10:00SUSY 2016: Day Four Session One<div dir="ltr" style="text-align: left;" trbidi="on">
I didn't try to liveblog the first few days of <a href="https://indico.cern.ch/event/443176/">SUSY</a>, which was a mistake. It turns out that doing this really does help me focus and pay attention. So I'm starting with Thursday, which happens to be the flavour session.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195558/attachments/1304409/1948822/bozzi_SUSY2016v2.pdf">9:00 am</a>: <i>Quark Flavour Physics</i>, Concezio Bozzi</b><br />
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Flavour physics in the SM is highly predictive (in the quark sector). Equivalently, this means that it is a good avenue for searching for new physics. A brief overview of the current experimental facilities: LHCb, Belle and even the general detectors.<br />
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Recent progress in measuring the unitarity triangle angle γ; uncertainty at LHCb down to 8%, about half of previous efforts.<br />
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Long-standing tension in measurements of V<sub>ub</sub> between inclusive and exclusive measurements. Probing at LHCb measuring the ratio V<sub>ub</sub>/V<sub>cb</sub>, which is non-trivial at a hadron machine as we can't use the beam energy as a constraint. Exploit rare decays of Λ<sub>b</sub> baryons, suppressing backgrounds with isolation criteria and (measurable) flight direction as kinematic constraint. Different measurement to previous exclusive observables based on B decays; agrees with exclusive result over inclusive measurement. Excludes possible right-handed currents as explanation for discrepancy.<br />
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New measurements of mass difference on D-sector (D versus D<sup>*</sup>) that indirectly constrains V<sub>td</sub>.<br />
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CP violation in B mixing another prior tension with SM. LHCb does not agree with this tension, but there is still an order of magnitude to go in improving the experimental error before it can compare to the theory uncertainty.<br />
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Probing the second (squashed) unitarity triangle. Interesting measurement in that it looks at interference effects in various b to c decays.<br />
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This talk is running into the standard experimental plenary talk problem: lots of results, little context.<br />
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Jumping ahead to the discrepancy in the B to K<sup>*</sup>μμ differential distributions, LHCb has performed a full angular analysis with 8 differential observables. 3σ discrepancy seen, also in a related point in Belle. Some efforts to explain using effective operators; when all observables are included, it is not clear how significant this result is. Claim from Ciuchini <i>et al</i> that can be explained by long-distance charm loops. More data needed to help resolve this question.<br />
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Deviation in lepton universality in B decays is still there. LHCb can exploit presence of second (hadronic) B and large b quark boost to perform superior measurements. Combined measurement deviates by 4σ. Many related observables to be probed in the near future that will help understand this case.<br />
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<i>Questions</i><br />
Dominant uncertainties in B to K<sup>*</sup>μμ decays? Plots shown were for asymmetries, so robust against small systematics.<br />
Question on role of right-handed currents in Vub measurements, but I missed it.<br />
Questions from the chair of the session where I literally could not make out the question.<br />
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<b><a href="https://indico.cern.ch/event/443176/contributions/2195559/attachments/1304202/1949621/flavor-susy-2016.pdf">9:30 am</a>: <i>Flavour Physics Theory</i>, Xiao-Gang He</b><br />
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Worth remembering: we now know there are only three generations. Additional heavy generations getting their masses from the Higgs can be excluded already from measurements of the Higgs couplings to diphotons/digluons. Light states including extra light neutrinos are excluded from measurements of the <i>Z</i> decay; cosmology gives the same bound on the number of neutrino species. Which is a very powerful & interesing recent result, when you think about about it.<br />
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Three generations of particles in general must mix. But the fundamental flavour question is why the mixing has the pattern that it does: hierarchical in the quark sector and democratic in the lepton sector. A related "problem" is that so far, the SM explains everything: there is no need for NP, which means we have no hard guidance in how to answer these questions.<br />
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First choice for an anomaly to discuss: small deviation in branching ratio for B<sub>d</sub> to μμ. Which is what, 2σ? But "it works with SUSY". Whatever. Other anomalies involving B decays, some of which were covered in the previous talk. It's hard to follow this talk, partly because how fast the speaker is talking, and partly because his slides are absolutely crammed with text, formulae and tables with no clear structure.<br />
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Three whole slides on MFV. Looking ahead, I'm not quite sure why.<br />
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OK, he is actually using this in his discussion of flavour-violating Higgs decays. I just couldn't recognise it among all the clutter. Conclusion is ... CP violating Higgs decays might exist?<br />
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Jumping through things too fast for me to understand what points, if any, are being made.<br />
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But we come to SO(10) flavour. Then a discussion of relating the 750 GeV diphoton excess to a flavour-related field. Or, as far as I can tell, taking the usual model of extra scalar and asserting it is related to flavour. Unrelated to a GUT, why are they in the same section? Another random thing shoved into the same section: the recent Be anomaly and possible 17 MeV boson.<br />
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You know what this reminds me of? The comment I made in the previous talk. Lots of basically unrelated things given one or two slides at most. In an experimental talk it's somewhat understandable (though why I tend to dislike experimental plenaries). In a theory talk, I think it shows you need to learn to edit.<br />
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<b>10:00 am: <i>Latest Results from Neutrino Oscillation Experiments</i>, Anelmo Cervera Villanueva</b><br />
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A general talk from a T2K speaker. A straightforward review of neutrino sources and mixing. Then oscillations, the fundamental tool for measuring neutrino flavour parameters.<br />
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Experimental strategies. θ<sub>13</sub> with reactor measurements, ν<sub>e</sub> disappearance at short-baseline experiments. Long-baseline searches for ν<sub>e</sub> appearance gives sensitivity to δ<sub>CP</sub> as well. Daya Bay is the most notable one at the moment, since it made the discovery. Note that its source is the fourth largest nuclear reactor in the world, which helps give it such good statistics. Double-Chooz has not updated since Moriond while Reno is mentioned.<br />
<br />
T2K is an off-axis accelerator experiment with a 300km baseline. Current goal is to search for anti-ν<sub>e</sub> appearance. This will directly probe CP violation. Source is a 30 GeV proton beam at J-PARC. Detector off-axis because this leads to a quite peaked spectrum, and further choose the angle so that the peak is where the oscillation probability is maximised. Some evidence for anti-ν<sub>e</sub> appearance, but short of 5σ; results to be updated at ICHEP. Joint analysis gives 90% exclusion of δ<sub>CP</sub> equal to 0.<br />
<br />
NOνA in US another long-baseline accelerator experiment. Better sensitivity to hierarchy than T2K. Results give (modest) exclusion of maximal 2-3 mixing.<br />
<br />
"The combination of all current experiments will probably result in a measurement of the mass hierarchy and an indication of non-zero δ<sub>CP</sub> (2-3 sigma)." An actual measurement of δ<sub>CP</sub> requires the next generation of experiments. Quick review of those experiments: T2K phase II, Hyper-K and DUNE.<br />
<br />
<i>Questions</i><br />
Current significance on δ<sub>CP</sub>? No combined result yet, probably close (slightly above) to 2 sigma.<br />
What of JUNO in China? Will measure solar parameters and hierarchy. Solar parameters not so important at the moment.<br />
What upgrades planned for T2K II? Increased beam power, upgrades to near detectors and 30 times the exposure.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-17574453212497773342016-05-26T16:23:00.002+10:002016-05-26T16:23:39.831+10:00Planck 2016<div dir="ltr" style="text-align: left;" trbidi="on">
So I've been trying to run a liveblog as in previous years at Planck. However, I am going to have to call a premature halt to it. I have some other obligations that would interfere with taking these notes, even during the talks. I'll try to get some general thoughts on the conference out early next week, but this will be my last post during the conference itself. But this will be my last word this week.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-79063309802724486052016-05-25T23:15:00.001+10:002016-05-26T16:19:42.899+10:00Planck 2016 Liveblog: Day Three Session Three<div dir="ltr" style="text-align: left;" trbidi="on">
I skipped the second session to do some work. But it seems to have run quite late, with a knock-on effect that the conference lunch was delayed and so I've missed the start of the first talk this afternoon.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=143&confId=2534">3:00 pm</a>: <i>Top Partners: Flavour, CP and Production at the LHC</i>, Hugo Serodio</b><br />
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... was the goal here to have partial compositeness for the tops only? I literally don't know what he's doing that isn't review here.<br />
<br />
I think it is (well, bottom partial compositeness only). With so much text on the slides, this should have been stated somewhere. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=161&confId=2534">3:20 pm</a>: <i>Searching for signals of FCNC in the production of heavy resonances at the LHC</i>, Maria Eugenia Cabrera Catalan</b><br />
<br />
Heavy coloured states that decay not to <i>tt</i> or <i>jj</i>, but to <i>tj</i>.<br />
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Jet substructure methods. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=197&confId=2534">3:40 pm</a>: <i>Profiling Z' bosons using charge asymmetry in top pair production with the lepton-plus-jets final state at the LHC?</i> Declan Miller</b><br />
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A huge title and a huge number of slides: 121. Did some stuff.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=44&confId=2534">4:00 pm</a>: <i>Higgs lepton flavour violation and connection to neutrino masses</i>, Juan Herrero Garcia</b><br />
<br />
Higgs decay to τμ are a tantalising possible signal. Even if they go away, it will remain a sensitive signal of NP. Analysis (<i>e.g.</i> this morning) in terms of EFTs needs to be UV completed.<br />
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Relevant dimension 6 operators Yukawa-like and derivative-like. Latter usually ignored as redundant under EOM, but can be more useful for making contact with the UV physics.<br />
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UV completions must generate desired signal without violating bounds on τ → μγ. Different ways to open the effective operators: four different topologies using scalars and/or fermions. In some cases, cannot decouple the tau and Higgs decay modes; but in others, you can.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=162&confId=2534">4:20 pm</a>: <i>Charged LFV from Low Scale Seesaw Neutrinos</i>, Xabier Marcano</b><br />
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Study of inverse seesaw model.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-14081750973683438072016-05-25T16:54:00.002+10:002016-05-25T23:10:45.862+10:00Planck 2016 Liveblog: Day Three Session One<div dir="ltr" style="text-align: left;" trbidi="on">
Day Three already, and we have a full morning of plenary talks. I might skip some of the afternoon talks today, as I have a lot of work to do; we'll see how I feel after lunch. The theme for today would seem to be flavour.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=65&confId=2534">09:00 am</a>: <i>Recent results from LHCb and future prospects</i>, Arantza Oyanguren</b><br />
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Not good when the first talk starts late, but I reckon only about a quarter of attendees have shown up on time.<br />
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Interesting to start with a null result: exclusion of candidate tetraquark seen at D0.<br />
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No evidence for NP in V<sub>ub</sub>. But this part of the talk didn't seem too convincing as a resolution of the discrepancy.<br />
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All discrepancies go away.<br />
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OK, <i>something</i>. Decays in charm sector inconsistent with lepton universality at 4σ.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=140&confId=2534">09:30 am</a>: <i>Possible Flavour Anomalies</i>, Tobias Hurth</b><br />
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Focus on semi-leptonic penguin decays in B sector, in particular the question of how strong the need is for BSM to explain observations.<br />
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I got a little lost here. Would have helped if the people behind me hadn't talked for several minutes.<br />
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OK, I think the general point was to use the EFT language to study various observables in a model-independent way.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=163&confId=2534">10:00 am</a>: <i>Probing Flavour Dynamics at the LHC</i>, Kaladi Babu</b><br />
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Please be interesting.<br />
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Discuss three explanations of flavour: at high scale within GUTs, radiatively, and with a low-scale gauge theory.<br />
<br />
Within GUTs, consider SO(10) models. This has an obvious connection to neutrino masses. Two Higgses are needed/allowed, which leads to non-trivial connections between the quark and lepton Yukawa matrices. However, it's not exactly impressive:<br />
<blockquote class="tr_bq">
<i>The model has 11 parameters plus 7 phases to fit 18 known observables.</i><br />
<i>Predictions are consistent with experiments.</i></blockquote>
When inputs and outputs are equal in number, that's not exactly a shocking result. Most interesting point is that θ<sub>13</sub> is in line with pre-existing predictions. But then we move to other models based on different Higgs structure and some vector-like fermions:<br />
<blockquote class="tr_bq">
<i>Yukawa sector has 14 real parameters plus 8 phases to fit 18 measured flavour observables</i></blockquote>
More inputs than outputs, so you should be able to fit things.<br />
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Radiative models based on idea that 3rd generation Yukawas are tree-level, 2nd generation 1-loop suppressed and 1st generation are 2-loop suppressed. Lightness of leptons can be explained by an additional loop suppression. Need extra diquark/leptoquark scalars. These states are what make things interesting, as they can be searched for. Indirect bounds are not too severe, at TeV scale, so if they exist they might be within the reach of the LHC.<br />
<br />
Models can be extended to include radiative generation of neutrino masses. Upper limits on additional scalar masses; though allowed to be too heavy even for 100 TeV machine. Still, possible probes based on LFV observables.<br />
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Flavour gauge models are based on gauging anomaly-free subgroups of SM flavour symmetry. Several choices, but finite and smal set of models. Need exotic Higgses to break gauge symmetry. Yukawa structure comes from VEVs (overall scale remains free). Some additional protections, depending on VEV structure, that is possible and allows flavour guage bosons to be at TeV scale. I got a bit lost here.<br />
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Of course, TeV-scale scalars raises the possibility that the 750 GeV resonance could be explained this way. Some effort needed to avoid Tevatron constraints. Large coupling to photons comes from multiple charged Higgs present in model. Moderately large quartics (~ Yukawas squared) needed; tension but not excluded. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=168&confId=2534">10:30 am</a>: <i>Recent CMS Results</i>, Joao Varela</b><br />
<br />
The second general LHC talk. Looking through the slides, it looks much like the ATLAS talk from yesterday. To quote the conclusions:<br />
<blockquote class="tr_bq">
<i>Excesses from 8 TeV searches not (yet?) confirmed at 13 TeV</i></blockquote>
Apart from the 750 GeV brouhaha, I think that's the main point really, isn't it.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-46803331985470937312016-05-25T01:12:00.001+10:002016-05-25T16:49:22.425+10:00Planck 2016 Liveblog: Day Two Session Four<div dir="ltr" style="text-align: left;" trbidi="on">
For me, the last session of the day is BSM 3, AKA the 750 GeV session. I'm hoping this will be more interesting for me.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=52&confId=2534">5:10 pm</a>: <i>A toolbox for diphoton model building</i>, Manuel Krauss</b><br />
<br />
There are a lot of things a model builder must consider when trying to fit the excess. If we want to address all of them, automised tools make our jobs a lot easier. This talk is to advertise SARAH, a Mathematica package that will analytically generate things like masses, vertices and RGEs; then put all of that into SPheno for numerical study.<br />
<br />
In particular, new inclusion of calculating the <i>gg</i>/γγ decay rates up to NNNLO/NLO. This is all that's needed to get the associated cross sections. Radiative corrections cannot be ignored; in particular, factor of 2 in <i>gg</i> partial width.<br />
<br />
Applied to SUSY model with U(1)X and pseudoscalar. Most interesting point: easy to see that large width preferred by ATLAS excluded by vacuum stability constraints. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=67&confId=2534">5:30 pm</a>: <i>Radion/Higgs phenomenology and the diphoton excess at the LHC</i>, Anibal Medina</b><br />
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I'm not taking notes here because I know this paper quite well.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=90&confId=2534">5:50 pm</a>: <i>Drell-Yan Constraints on New Electroweak States and the Di-photon Anomaly</i>, Christian Gross</b><br />
<br />
The archetypal model involves new charged states, not too heavy. How can these be probed?<br />
<ul style="text-align: left;">
<li>Direct collider searches are model dependent. Limits range from 100 GeV for lepton-like states with SM charges, up to TeV for coloured states with exotic charges.</li>
<li>EW precision observables are not very constraining.</li>
<li>Modification of gauge beta functions is generally quite significant.</li>
</ul>
The modifications to the beta functions can show up in differential distributions of dimuon cross sections, measured into multi-TeV range. Can also alter forward-backward asymmetries, but this is currently less constraining.<br />
<br />
The resultant bounds are significant, but they don't quite exclude the relevant parameter space. However, they are not too far from it. Given that we are considering model-independent bounds, this is pretty good and raises the hope of a definitive test before too long.<br />
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<i>Questions</i> <br />
This is all one-loop; surely the necessary large Yukawas would have two-loop effects? Perhaps. Imposed Yukawa perturbativity to 3 TeV.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=105&confId=2534">6:10 pm</a>: <i>Characterising the 750 GeV diphoton excess</i>, Dipan Sengupta</b><br />
<br />
A number of things we'd like to know about the putative resonance: questions like spin, width, decay mode <i>etc</i>. Trying to resolve these using various kinematic distributions.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=194&confId=2534">6:30 pm</a>: <i>A closer look at the sgoldstino interpretation of the diphoton excess</i>, Pietro Baratella</b><br />
<br />
Non-zero gaugino masses imply sgoldstino-gauge boson coupling. This means that the resonance coupling to <i>gg</i>/γγ is related to the gaugino masses, a non-trivial constraint on the model. Leads to a low SUSY breaking scale, order several TeV. Suggests GMSB for flavour. Messenger mass can not then be too heavy; leads to inconsistency between gluino bounds and signal cross section.<br />
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Need to move to a (fine-tuned) limit with an anomalously light messenger, due to an accidental cancellation. This enhances the effective coupling, though it pushes things towards the strong coupling limit. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=17&confId=2534">6:50 pm</a>: <i>Di-photon excess illuminates Dark Matter</i>, Alberto Mariotti</b><br />
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Take the ATLAS width seriously. Must decay to something other than dijets/digamma. Choose DM to avoid constraints. DM parameters (assuming Dirac fermion) are then approximately fixed by demanding signal cross section, total width and relic density: mass ~ 300 GeV and resonance-DM coupling ~ 2.<br />
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Then we can ask if this is allowed. LHC searches in dibosons, monojets as well as DD limits. Taking a grand total of four benchmark points, 3 survive. All are close to DD bounds, so could be found in near future. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-51692527911343362012016-05-24T23:06:00.000+10:002016-05-25T01:07:57.677+10:00Planck 2016 Liveblog: Day Two Session Three<div dir="ltr" style="text-align: left;" trbidi="on">
Back from lunch, where I made the mistake of indulging in three glasses of wine. Time for some hardcore BSM, I guess.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=139&confId=2534">3:00 pm</a>: <i>Non-SUSY BSM searches at ATLAS and CMS</i>, Todd Adams</b><br />
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American in Spain compares our work to Columbus sailing off and finding a new world. Start with the 750 GeV diphoton excess, exciting but the only thing we can ultimately say is that we need more data, coming soon. Note that there is no evidence for a Zγ excess to go along with it. In a more general sense, too, the existence of this excess has ensured that many searches involving dibosons (for <i>e.g.</i>) have been extended down to at least that mass range.<br />
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Various mono-X searches. Much as we have come to expect from these channels. Dijet resonances, see above. It's all almost magical the way the experimentalists deal with their conditions to set these strong limits, but we increasingly face the problem that we end with nothing to suggest that the SM is not all there is.<br />
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Ditop resonance searches pushing RS KK gluon up to over 3 TeV with the initial run 2 data.<br />
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<i>Questions</i> <br />
Dijet searches at 750 GeV? Not sure if there are plans. Background is very large, which might make it pointless; would need good control of systematics.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=10&confId=2534">3:20 pm</a>: <i>Electroweak top-quark pair hadroproduction in the presence of Z' bosons in POWHEG</i>, Ingo Scheinbein</b><br />
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<i>Z'</i>s usually most constrained by leptonic final states, but this is not guaranteed. Special role of top quark motivates considering it as a final state. Because we are dealing with coloured objects, must consider NLO QCD corrections, not previously computed. Interference between signal and background is an order-1 effect.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=134&confId=2534">3:40 pm</a>: <i>Drell-Yan production of multi-Z's at the LHC</i>, Juri Faschi</b><br />
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That's multi-Z primes in the title. Unlike the previous talk, this uses the dilepton final state. Searches for single Z' resonances are well-understood, whether the Z' is narrow or wide. Here, consider what is the optimal strategy if multiple vector production is the leading channel. I think this is supposed to be motivated by some 5D string-inspired theory, but if that's the case, if would be good to say why diboson production will dominate. Seriously, I don't see how the first handful of slides connect to the rest of this talk.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=94&confId=2534">4:00 pm</a>: <i>Impact of LHC monojet searches on new physics scenarios</i>, Suchita Kulkarni</b><br />
<b></b><br />
Applying monojet searches to two scenarios. First is connected to 750 GeV particle, and to momentum-dependent DM couplings.<br />
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750 GeV particle is scalar mediator with effective couplings to gauge bosons. DM is fermionic. Monojet searches place non-trivial constraints that, in particular, exclude 45 GeV width.<br />
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Momentum dependence, blah blah blah. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=153&confId=2534">4:20 pm</a>: <i>Probing the interplay between TeV scale heavy vector resonances and top partners at the LHC</i>, Bithika Jain</b><br />
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Composite Higgs models where the vector resonances decay to top partners rather than directly to the SM. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-4679303358661697842016-05-24T19:38:00.000+10:002016-05-24T23:02:19.706+10:00Planck 2016 Liveblog: Day Two Session Two<div dir="ltr" style="text-align: left;" trbidi="on">
The first of three parallel sessions today, and I've decided on the SUSY 2 session. Though looking at the talks, there seems to be more of a DM theme with two talks not necessarily being supersymmetric.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=111&confId=2534">11:30 am</a>: <i>Relic density of wino-like dark matter in the MSSM</i>, Pedro Ruiz-Femenia</b><br />
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Study of Sommerfeld effect away from pure wino/Higgsino limits. Eh. Some mixing weakens ID constraints.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=57&confId=2534">11:50 am</a>: <i>Blind spots and their impact on neutralino relic abundance in the NMSSM</i>, Pawel Szczerbiak</b><br />
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Point.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=100&confId=2534">12:10 pm</a>: <i>Simplified DM models with the full gauge symmetry</i>, Alexander Natale</b><br />
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Prior effective operator studies of DM models at LHC/DD have limitations. LHC models that do not respect full EW symmetry can lead to spurious contributions from longitudinal polarisations of gauge bosons. DD must be concerned about running from EW scale to low-energy scattering scale, which will generally mix operators and can lead to important effects.<br />
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Simplified models written in full EW phase look to avoid this. Model involves multiple scalar mediators allowing variable couplings to different chirality/flavour quarks. DM then excluded by DD unless it is light, < 10 GeV.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=9&confId=2534">12:30 pm</a>: <i>Right-handed sneutrino dark matter in the mSUGRA</i>, Shankha Banerjee</b><br />
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Add right-handed neutrino superfields for neutrino masses. Take limit where superpotential respects lepton number, so sneutrinos are light and can effect EW scale pheno; right-handed sneutrinos can be LSP.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=73&confId=2534">12:50 pm</a>: <i>The Coannihilation Codex</i>, Anna Kaminska</b><br />
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Complete classification of coannihilating simplified models, within moderate assumptions. In turn allows a classification of LHC processes searching for coannihilating states, in particular identify unused search strategies.<br />
<br />
Assumptions are that DM is usual thermal WIMP, coannihilation involves only 2 to 2 processes, and no new fields with spins larger than 1. Classification is then a simple matter of enumerating all possible SM quantum numbers. List consists of finite set of families characterised by free hypercharge and isospin quantum numbers. Distinct classification of models by <i>s</i>-channel, <i>t</i>-channel and hybrid coannihilation.<br />
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At LHC, can pair produce coannihilating partners/mediator states with gauge interactions. Can also produce states directly through coannihilation couplings, directly probing those processes. The same diagrams lead to decays of the partner states, giving a general signal.<br />
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<i>s</i>-channel models have interesting complementarity between resonance searches for mediators, and production of resonance final states plus MET from decays of coannihilating partners. Allows complete test of paradigm.<br />
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<i>t</i>-channel models more SUSY-like, with compressed spectra and always some MET. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-57029057275829475182016-05-24T16:38:00.002+10:002016-05-24T19:30:47.116+10:00Planck 2016 Liveblog: Day Two Session One<div dir="ltr" style="text-align: left;" trbidi="on">
We move to the second day of the conference, and the only plenary session of the day. Which is fine by me, I like the format for the conference this year more than last year. We have a selection of collider phenomenology talks, though the connections seem a bit limited to me.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=33&contribId=167&confId=2534">09:00 am</a>: <i>Recent ATLAS results</i>, Martine Bosman</b><br />
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Always good to start with an experimental talk. It keeps us (me?) honest. Though I'm a little surprised we don't have talks from both ATLAS and CMS on the same day (CMS talk tomorrow).<br />
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Ongoing efforts to rediscover the SM at 13 TeV. Small excess in <i>WW</i>/<i>WZ</i> production, but might be resolved with improved theoretical predictions. New top mass measurements push errors from ATLAS alone to less than 1 GeV.<br />
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Higgs physics: legacy of half a million produced at run 1, of which <i>e.g.</i> 1000 decayed to diphotons, 65 to the golden channel, or 30000 to ditau. ATLAS alone in excess of 5σ in γγ, <i>ZZ</i> and <i>WW</i> channels; 4σ in ττ; less than 2σ in <i>bb</i>. Higgs mass measurement still statistically dominated; improvements to come. Observations at 13 TeV beginning.<br />
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Resonance searches boring except for the obvious one. Clear from the likelihood plots in the mass-width plane that the width is poorly constrained by the ATLAS 13 TeV data; might not be true at 8 TeV, but this is not clearly shown here.<br />
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SUSY searches at 13 TeV already pushing exclusions into new ground, <i>e.g.</i> 1.5 TeV gluino. Small excess in dilepton channel at 8 TeV seems to be persisting so far, but the significance is not very big. Still, definitely something to watch out for.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=33&contribId=22&confId=2534">09:30 am</a>: <i>Is supersymmetry still alive?</i> Werner Porod</b><br />
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The title is a question, so the answer is no. Another person who didn't feel any need to put their talk online in advance.<br />
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Before the LHC, the usual approach was to try and fit all low-energy data with something like CMSSM or mSUGRA. This pointed to light sfermions below a TeV. Of course, that hasn't happened. Additionally, the Higgs has changed from a search target to a precision observable that NP must explain. This is the well-known MSSM challenge for the Higgs mass, with radiative corrections of nearly 100%. In minimal GMSB, for example, the stops are forced too heavy to be seen at the LHC.<br />
<br />
You can do new fits if you want. It gives what you'd expect, namely preferred points just above the limits. Also, if you include the muon anomalous magnetic moment, then the CMSSM is actually excluded at 90%. Even if you ignore that, you run into problems with charge/colour breaking minima. Not impossible but you're sitting no the boundaries.<br />
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A similar thing can happen in Natural SUSY. Light stops are allowed by observation, but if the gluino is also heavy it will tend to run to a CCB minima before the GUT scale.<br />
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If stops <i>and</i> gluinos are heavy, only Higgsinos are light, difficult to see. DM relic density too low but can't be excluded, or discovered with Xenon 1T. Can do something with monojets at LHC up to maybe 250 GeV exclusion. So this will live for some time, it seems.<br />
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Extended gauge groups based on SO(10) or E8 have two effects. Tree-level contribution to Higgs mass increased, so smaller radiative corrections needed; and have right-handed sneutrinos that can be DM.<br />
<br />
<i>Questions</i> <br />
Anomalies? That's what right-handed neutrinos are for.<br />
Gluino bounds and fine tuning? ...<br />
Generalised GMSB can have lighter stops at TeV scale? What of CCB? Seems not to be resolved here either. <br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=33&contribId=207&confId=2534">10:00 am</a>: <i>Higgs LFV decays</i>, Antonio Delgado</b><br />
<br />
Mild excess (2.4σ at most) in h → μτ. However, this is for all intents and purposes zero in the SM. Interestingly, this corresponds to a LFV Yukawa Y<sub>μτ</sub> Y<sub>τμ</sub> ~ m<sub>μ</sub> m<sub>τ</sub>/v<sup>2</sup>. The challenge is to induce this decay without inducing LFV decay of leptons above the strict bounds. In a simple SM EFT, the latter exclude the former. This suggests going to a model with more than one source of EWSB.<br />
<br />
First effort: SUSY with LFV soft terms (slepton masses and A-terms). Need large A-terms relative to slepton masses to get a large enough rate, which runs into charge-breaking vacua.<br />
<br />
Second effort: vector-like fermions. Use four-fermion operator as source of LFV. Leads to fermion masses in the 10 TeV range, with 20 TeV cut-off of dimension 6 operator. This can be weakened; there are three possible fermion contractions, and only one generates τ → μγ. Taking that one to be zero is unstable under the RGE, but suggests you could have a moderate suppression.<br />
<br />
<i>Questions</i><br />
Non-SUSY 2HDMs? Easy? Depends, but typically one tends to be heavy.<br />
Muon g-2? Not considered in this study.<br />
Debate rising over EFT allowed or not.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=33&contribId=47&confId=2534">10:30 am</a>: <i>CP Violation and Invisible Higgs Decays at the LHC</i>, Jorge Romao</b><br />
<br />
2HDM with usual softly-broken Z2 has, in general, irreducible complex phase.<br />
<br />
You know, it's rare to see a speaker completely skip any motivation for their work.<br />
<br />
I guess there's no problem in computing the bounds on these models, it's just all a bit meh. </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-22315676322130173332016-05-24T01:23:00.000+10:002016-05-24T16:32:56.952+10:00Planck 2016 Liveblog: Day One Session Four<div dir="ltr" style="text-align: left;" trbidi="on">
Last session of the day, BSM 1. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=18&confId=2534">5:10 pm</a>: <i>Phenomenology of Decoupled New Physics with the SM EFT</i>, Jeremie Quevillon</b><br />
<br />
Precision measurements matching UV physics to observables. In particular, what of Higgs as portal to new physics? Model-independent constraints: no need to redo analyses.<br />
<br />
Important note: <i>must</i> use mass-independent renormalisation scheme, otherwise higher-dimension operators will not decouple. But then integrating out of heavy fields and matching must be done by hand. Can be done with Feynman diagrams or by path integrals. This technique (CDE, covariant derivative expansion) improves and simplifies this piece.<br />
<br />
This is the rare example of a talk I'd prefer to last an hour.<br />
<br />
Point is: can do all matching in a general language, such that <i>any</i> UV theory can use pre-calculated expressions to derive one-loop matching with minimal effort. <br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=156&confId=2534">5:30 pm</a>: <i>Searching for heavy scales in the Electroweak Effective Theory</i>, Joaquin Santos Blasco</b><br />
<br />
EWEFT theory assuming arbitrary (non-linear) Higgs representation. Fermions to be added. Add bosonic singlet/triplet resonances (consider only one at a time). Impose additional constraints for UV consistency, <i>e.g.</i> from Weinberg sum rules.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=29&confId=2534">5:50 pm</a>: <i>One-loop effective Lagrangians after matching</i>, Jose Santiago</b><br />
<br />
"Goal: Generate a UV/IR dictionary (map <i>all possible UV completions of the SM</i> to the Wilson coefficients of the SM effective Lagrangian)" (emphasis mine).<br />
<br />
At tree level and dimension-6, this is done?!? except for mixed contributions. Dimensionful couplings mean states of different spin can simultaneously contribute. To be completed soon.<br />
<br />
One loop is next. Many operators can only be generated at this order, not tree level (both in general and in specific models). Number of contributions is so large that automation is necessary. Matching in presence of linear couplings (mixings) major task. Development of new tool <i>MatchMaker</i> based on FeynRules/FORM/other to do this. Write your FeynRules model as input and the rest is taken care of.<br />
<br />
<i>Questions</i><br />
Tensors? In principle possible but not in the first release.<br />
Arbitrary UV? <i>e.g.</i> String RS involved parametrically light high-spin states. OK.<i> </i> <br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=81&confId=2534">6:10 pm</a>: <i>Mass hierarchy and naturalness from TeV scale strong dynamics</i>, Roberto Frezzotti</b><br />
<br />
That sure was a talk.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-63328961209742789072016-05-23T23:01:00.001+10:002016-05-24T01:12:28.395+10:00Planck 2016 Liveblog: Day One Session Three<div dir="ltr" style="text-align: left;" trbidi="on">
Unlike some Plancks I've been to, here we're into the parallel sessions from day one. First off, I've chosen to attend the <i>Higgs I</i> session.<br />
<br />
Also, mostly unrelated but lunch today was the best conference food I've ever had. <br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=32&confId=2534&sessionId=4">3:00 pm</a>: <i>Higgs Physics</i>, Elisabetta Gallo</b><br />
<br />
Run 1 and 2 results from both CMS and ATLAS. Over 600 different production/decay channels combined. Result of it all is a global fit on signal strength μ = 1.09 with 10% errors. All combined production modes agree with SM at 1σ, except ttH; all decay modes except ZZ. Combined searches for ττ observed at 5σ. Differential cross sections in <i>WW</i> also in excellent agreement (high statistics, MET).<br />
<br />
At run 2, only 2.7 ifb of data used due to problem with solenoid cold box (now fixed). Pile-up of 13. Signals in golden channel (4l) a bit low at ATLAS/CMS so far. Similar with γγ. Both channels have better S/B at run 2, due to improved analysis.<br />
<br />
<i>ttH</i> production enhanced by factor of 4. Use MEM to remove <i>ttbb</i> background. Trilepton channel at CMS <i>persists!</i><br />
<br />
Double Higgs production a target: classic sign of NP in form of new resonances or enhanced self-coupling. Possible observation of SM process so can exclude some models.<br />
<br />
<i> </i><br />
<i>Questions</i><br />
Bounds on non-resonant diHiggs? DNK<br />
Ratio of BRs? All look good except bb/ZZ, but that is probably not meaningful.<br />
Excess in ttH? Run 2 has net deficit if sum all channels.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=87&confId=2534&sessionId=4">3:20 pm</a>: <i>Singlets in Composite Higgs Models in light of the LHC di-boson searches</i>, Thomas Flacke </b><br />
<br />
Minimal UV models of composite Higgs involve additional states: coloured light states and additional scalars producing diboson signals. Specifically, demanding no new elementary scalars, a simple hyper-colour group, a Higgs and top-partners excludes minimal symmetry breaking group SO(5)/SO(4). Smallest are SU(4)/Sp(4), SU(5)/SO(5) and SU(4)xSU(4)/SU(4). All models contain coloured pNGBs; and two spontaneously broken U(1) symmetries leading to SM singlets. One is anomalous and associated states heavy, while the other only couples to SM through WZW term.<br />
<br />
Coloured Goldstones lead to searches in four tops. Easy to apply limits.<br />
<br />
Existence of (potentially light) singlet attractive for 750 GeV study. List of models that can explain this notably truncated; all in reach of near-future searches.<br />
<br />
<i>Questions</i><br />
What effect does giving mass to singlets have? Interesting question, direct are of work.<br />
Can SM couplings be used? No, because singlet. But might depend on top Yukawas, depending.<i> </i> <br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=42&confId=2534&sessionId=4">3:40 pm</a>: <i>New physics and signal-background interference in associated HZ production at LHC</i>, Alberto Tonero</b><br />
<br />
<i>pp → ZZ </i>or<i> HZ</i> good channels to constrain Higgs sector, especially at high momentum transfer. Constrain dimension-6 effective operator.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=138&confId=2534&sessionId=4">4:00 pm</a>: <i>Higgs mass from (super)-split supersymmetry</i>, Jae-hyeon Park</b><br />
<br />
First post-title slide: nothing but equations.<br />
<br />
When SUSY scale is large, must resum logarithms. Match quartic at MSUSY and run down. This was done in 2014, found upper limit of 10<sup>12</sup> GeV (high-scale) or 10<sup>8</sup> (split). Equivalent to instability in SM potential near that scale vs positive definite nature of quartic in MSSM.<br />
<br />
Clever idea exploiting non-decoupling nature of a bounce solution that I didn't quite follow. <br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?contribId=151&confId=2534&sessionId=4">4:20 pm</a>: <i>Opening the Higgs portal window</i>, Javier Quilis Sancho</b><br />
<br />
Standard scalar singlet Higgs portal model has many nice properties. This includes that it can be ruled out. LZ can do this except for tiny region right on the resonance.<br />
<br />
However, we can add one extra unstable Higgs portal scalar. Removes lower bound on portal coupling for large masses, leading to essentially no constraints. Doesn't work at low masses, because <i>H<sup>2</sup>S<sub>1</sub>S<sub>2</sub></i> portal coupling leads to invisible decays.<br />
<br />
<i>Questions</i><br />
Was Sommerfeld enhancement included? No.<i> </i> </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-47812524244911038072016-05-23T19:41:00.000+10:002016-05-23T22:56:35.452+10:00Planck 2016 Liveblog: Day One Session Two<div dir="ltr" style="text-align: left;" trbidi="on">
Second session of the day looks quite technical. Thankfully, at least for me, most other plenary sessions look more phenomenological. We're running a few minutes behind already, thanks to the first session running about 15 minutes over.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=32&contribId=33&confId=2534">11:30 am</a>: <i>Aspects of string phenomenology and new physics</i>, Ignatios Antoniadis</b><br />
<br />
People should really put their talks on the website before giving them.<br />
<br />
Problem of scales: Dark Energy, Electroweak, Inflation and Planck. Different scales implies hierarchy challenges. Possible that some of these could be connected. <i>e.g.</i> famous ADD large extra dimension theories, where true quantum gravity scale is close to EW scale. Accelerator signals come at four different scales: gravitational radiation in the bulk (missing energy), string vibrations (dijet resonances), KK resonances, and extra U(1)s and anomaly induced terms.<br />
<br />
D-branes used to generate gauge/fermion multiplets in the usual way. Green-Schwarz mechanism: ALPs. Generation of baryon/lepton number U(1)s automatically.<br />
<br />
750 GeV resonance, spin-0/2 (but both closed string) explanation. Related to anomaly cancellation; suppresses mass by order of magnitude from string scale.<br />
<br />
<i>Questions</i><br />
Does string theory predict relative couplings to gluons/photons? No.<br />
Can explain 750 GeV using weak couplings to Planck scale if cross section is a bit smaller, say 3fb.<br />
Strong CP problem? ...<br />
How can 750 GeV explanation be checked? String scale is not too large; LHC can not fully exclude, but 100 TeV can.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=32&contribId=175&confId=2534">12:00 pm</a>: <i>Holographic renormalization group a la Wilson</i>, Manuel Perez-Victoria</b><br />
<br />
Holography: UV/IR conection. <i>e.g.</i> AdS metric invariant under isometry <i>x → tx</i>, <i>x → tz</i> (scale invariance). Theories around non-trivial solutions to gravity are dual to CFTs. The duality interconnects RGEs to gravity EOMs.<br />
<br />
Defining your terms is nice.<br />
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<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=32&contribId=181&confId=2534">12:25 pm</a>: <i>Natural SUSY from x-dimensions</i>, Mariano Quiros</b><br />
<br />
Little hierarchy problem can be phrased as tendency for heavy stops to destabilize the EW vacuum. Attempt to increase Higgs mass with either additional <i>D</i>- or <i>F</i>-terms. <i>D</i>-terms require the Higgs to be charged under the new gauge group and imposes anomaly cancellation conditions. <i>F</i>-terms do not require an extended gauge sector. These correspond to adding a singlet (NMSSM) or triplet (TMSSM) to the theory.<br />
<br />
Singlets are simpler, but tadpoles are a serious problem. They generically destabilize any hierarchy. This can only be forbidden by a symmetry, but then you have domain wall problems. Triplets have tadpoles forbidden by gauge symmetry, but the challenge their is that EWPO constrain their VEVs to be small.<br />
<br />
Go to 5D theory with Scherk-Schwarz breaking of SUSY. Basic MSSM in flat 5D to start. Bulk N = 2 SUSY broken to N = 1 by orbifolding, and all SUSY broken by twisted boundary conditions. The Higgs soft masses are automatically such that they satisfy focus point conditions, <i>i.e.</i> the tree-level VEV is zero independent of the scale of the soft masses, and EWSB is purely radiative. This is accomplished with bulk triplets and boundary-localised couplings to the Higgs.<br />
<br />
Third generation sfermions boundary-localised. Then only light sparticles, automatically natural spectrum. DM is stau sneutrino (DD?). DM is heavy (280 GeV) which leads to no collider stop bounds. Indirect bounds from gluino searches bound to 550 GeV.<br />
<br />
<i>Questions</i><br />
LSP DD question. Indeed, can not be DM: must be unstable.<i></i><br />
Stability of EW vacuum: not a problem now due to light stops, plus 1/R can be taken large.<br />
Flavour physics: first two generations have aligned masses.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-76182457613822769522016-05-23T17:04:00.002+10:002016-05-23T19:41:38.945+10:00Planck 2016 Liveblog: Day One Session One<div dir="ltr" style="text-align: left;" trbidi="on">
It's that time of year again, the time I write most of my posts here: Conference Season! I skipped Pheno this year for a variety of reasons, so I'm starting things off at <a href="http://congresos.adeituv.es/planck2016/">Planck 2016</a>, in the city of Valencia. I've never been to this part of Spain before, but what little of the city I've seen so far does look very nice.<br />
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After the usual opening remarks, it seems we start with a session on astrophysics and cosmology.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=1&contribId=177&confId=2534">09:30 am</a>: <i>Results from the Planck Satellite and implications for particle physics</i>, Julien Lesgourges</b> <br />
<br />
"Very happy to open Planck with some Planck."<br />
<br />
Direct observations: temperature and polarisation. Derived map: lensing. Four independent two-point correlation functions: TT, EE, TE, φφ. Four (complicated) functions to fit gives information from early Universe. Minimal ΛCDM means six parameter fit. Fit is good.<br />
<br />
Planck satellite stopped taking data some time ago, but analysis is difficult and still ungoing. TT data is now as good as it can be for <i>l </i>> 30 or so (cosmic variance limited). Last month, TE/EE data from LFI detector at low multipoles. Still some systematics in TE/EE/φφ spectra, hope to have finished work by 2017.<br />
<br />
Most recent results at low multipoles: information on reionisation at small redshift. Preference to relatively recent reionisation. Resolves small prior tension between CMB and astrophysics (Quasars, Lyman-α) data. Also, increases bounds on neutrino masses: Planck alone at < 140 meV. Puts greater pressure on inverted hierarchy.<br />
<br />
Bounds on WIMP annihilation improved with Planck polarisation data release. Depending on annihilation channel, exclude the region 10 to 40 GeV.<br />
<br />
Most interesting facet might be the affect on inflation. ``The'' inflationary model, φ<sup>2</sup>, is in increasing tension with the most recent Planck polarisation results; needs official analysis. Would be more interesting if I worked on this type of model-building. Convex models in general more and more disfavoured. Preferred models: hilltop (some fine-tuning, connection to SSB); flat direction lifted by radiative corrections (SUSY); exponential potential (moduli stabilisation). Last are interesting in that they give lower bound on <i>r</i> of 0.01. This can be tested within a decade or so.<br />
<br />
<i>Questions:</i><br />
What of Higgs inflation? Currently disfavoured due to instability of potential.<br />
Sterile neutrinos? Cannot improve the quality of the fit. (Can avoid the bounds in various ways.)<br />
Tension in Hubble parameter? Increasing with more data. Now at 3σ, cannot be ignored. Could, of course, be systematic. Some have suggested a systematic between local and global measurements; but not part of standard cosmology. Could be model: CMB measurement requires some type of extrapolation.<br />
Extensions beyond ΛCDM? Must keep good fit. <i>e.g.</i> WDM can not be distinguished using CMB data. Occam's razor.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=1&contribId=173&confId=2534">10:00 am</a>: <i>The new era of gravitational wave astronomy</i>, Alicia Sintes</b><br />
<br />
Now that we have discovered them, GW opens a new avenue of observations. High frequencies correspond to low energies here. High-frequencies (stellar masses) are the only things that can be probed with ground-based experiments.<br />
<br />
First science run of Advanced LIGO was still well short of design sensitivity. Observation targets: coalescing binaries, bursts (core collapse plus ??), continuous signals (spinning neutron stars) and stochastic searches (primordial GW).<br />
<br />
Advanced LIGO will ultimately increase sensitivity over LIGO by a factor of 10; hence volume of space accessible increases by 1000. Improvement is even more dramatic at low frequency end. Gain so far by factor of 3+.<br />
<br />
Second observed candidate; only at 2σ (compare 5 for initial event).<br />
<br />
Observation requires spectral matching to be robust. Final fraction of a second before merger can only be done with numerical relativity. This can take weeks to generate.<br />
<br />
Only half of initial run released so far. 90% chance of a second event. Expect 5 to 10 events from run 2 this autumn.<br />
<br />
<b><a href="https://indico.ific.uv.es/indico/contributionDisplay.py?sessionId=1&contribId=178&confId=2534">10:30 am</a>: <i>Constraining non-standard neutrinos with cosmic microwave background observations</i>, Massimiliano Lattanzi</b><br />
<br />
Possible extensions to standard picture obviously broad, but primary focus: non-standard interactions; non-thermal distribution; steriles; and large lepton asymmetries. For time reasons, only can cover first two.<br />
<br />
NSI: basically neutrinos plus coupling to either light/massless scalar or light pseudoscalar. Cross section then goes like <i>T</i><sup>-2</sup>. This leads to a recoupling of neutrinos as late time: <i>σv/H </i>~ 1/<i>T</i>, 1/<i>T</i><sup>3/2</sup> depending on era. Collisions drive power from higher moments to only monopole (density) and dipole (pressure).</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-73684993888893848252016-04-14T02:10:00.001+10:002016-04-14T02:10:53.141+10:00Link Round-Up<div dir="ltr" style="text-align: left;" trbidi="on">
Looking through the news, I saw a surprising number of stories I could write posts on. Rather than do them all justice, however, I'm just going to through a list of links together with a couple of sentences of commentary.<br />
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<ul style="text-align: left;">
<li>Proving that homophobia does not require an Abrahamic religion, a gay couple in China have been <a href="http://www.bbc.com/news/world-asia-china-36032383">denied the right to marry</a>. Still, it sounds like China may go the way of other industrialised nations in the near future.</li>
<li>We had one day's official holiday today for parliamentary elections. Despite that, I didn't bother to pay much attention to the whole affair. But it seems that, in contrast to what seemed likely beforehand, the governing party <a href="http://www.bbc.com/news/world-asia-36033773">will lose seats</a>. If so, it probably kills their planned weakening of legal protections for workers, so I'm not going to be losing any sleep over that.</li>
<li>The French PM has <a href="http://www.theguardian.com/world/2016/apr/13/french-pm-ban-islamic-headscarves-universities-manuel-valls">called for a ban</a> on Muslim headscarves at French Universities, because he didn't think the French Muslim community was isolated and angry enough.</li>
<li>The Guardian has released a study into the <a href="https://www.theguardian.com/technology/2016/apr/12/the-dark-side-of-guardian-comments">nature of their online comment sections</a>. No surprises, there are no small number of ugly comments with a distinct racial and sexist basis. But concrete evidence is still a useful tool in combating it.</li>
<li>Potential good news for pro-EU Brits, with <a href="http://www.telegraph.co.uk/news/2016/04/13/pmqs-live-david-cameron-jeremy-corbyn-eu-referendum-brexit-fund/">infighting among the various Brexit camps</a>. The founder of one of the groups competing to be the "official" pro-Brexit campaign is threatening to sue after losing out to Vote Leave, headed by the Justice Secretary. When Nigel Farage looks calm and sensible by comparison, you should know you've gone too far. This could also delay the vote till October, by which time Cameron and Osbourne might have recovered from the recent highly damaging fallout from the Panama Papers.</li>
</ul>
</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-50084687610640598962016-04-14T01:52:00.003+10:002016-04-14T01:52:57.528+10:00Privatised Social Service Fails<div dir="ltr" style="text-align: left;" trbidi="on">
From the <a href="http://www.theguardian.com/society/2016/apr/12/patients-wait-hours-for-ambulances-nhs-transport-service-privatised-sussex">Guardian</a>, we hear of systemic failures with the privatisation of the NHS ambulance service:<br />
<blockquote class="tr_bq">
Hundreds of patients including people with cancer and kidney failure
have missed important appointments for treatment because ambulances did
not arrive to take them to hospital, after privatisation of NHS non-urgent transport services in Sussex this month. </blockquote>
<blockquote class="tr_bq">
Some elderly patients have had to wait more than five hours for
ambulances and been stuck at hospital for long periods after their
appointments because the transport service, now run by the private firm
Coperforma, has proved so unreliable.</blockquote>
<blockquote class="tr_bq">
Patients, relatives, NHS bodies and local MPs have severely
criticised the service’s performance, and a trade union representing
ambulance crews said it was an “absolute shambles”. The NHS
organisations that awarded the four-year, £63.5m contract have now
launched an investigation.</blockquote>
I'm shocked, <i>shocked</i> I tell you to hear that privatising an important public service has lead to a drop in quality. It's never happened before, except for all those times that it has.<br />
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My initial thought on seeing this story was to make a sarcastic comment on the famous definition of insanity; repeatedly doing the same thing and expecting a different outcome. But then I remembered that privatisation has nothing to do with trying to improve services. It's about cutting costs (and, when Brown was chancellor, keeping what costs were left off the books entirely). It's about deferring responsibility; if this had happened under a government-run service, the blame would have fallen on the local government. As it is, the blame <i>mostly</i> falls on the company behind things. And to some extent its about the ideological idea that the private sector is always better, despite the fact that the usual free market arguments are poor fits to social services for a number of reasons.<br />
<br />
Mostly, though, it's about the fact that government contracts are lucrative business. Bad press like this doesn't matter so much, when the companies vying for contracts are busy schmoozing the relevant politicians. Like many companies, they spend a lot advertising; in this case selling themselves and their products not to the general public, but to a small number of people holding the public's purse strings. Companies get healthy long-term contracts; politicians get wined, dined and, sometimes, hired by these same companies for their "expertise", once they leave office; it's win-win! </div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-13875728637204626072016-03-23T03:21:00.001+11:002016-03-23T03:21:52.005+11:00The Amusing American Primary<div dir="ltr" style="text-align: left;" trbidi="on">
By which I mean the Democratic one; the Republican side is just scary.<br />
<br />
After Sanders lost all five states last week, he faced more calls to drop out of the race. There's a lot of things in that statement alone that amuse me. One is that in Illinois, Clinton and Sanders split the delegates equally; while in Missouri, Clinton won one extra delegate on the basis of 1500 votes<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#1" name="top1"><sup>1</sup></a>. A small shift in those two elections, and there'd probably be a fair bit speculation about a Sanders comeback, for no real change in the status of the election.<br />
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Another thing is that we have only just passed the halfway mark of the primay, with the release of the Democrats Abroad results yesterday. And yet people have been advocating that Sanders drop out since Super Tuesday<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#2" name="top2"><sup>2</sup></a>. This all strikes me as part of the US's peculiar attitude towards democracy, with elections for positions that in most countries are appointed yet at the same time trying to suppress voters from actually having their say.<br />
<br />
Plus, for the Democrats, as long as Sanders continues to run a more positive campaign, I don't see a long primary as a bad thing. It didn't hurt Obama to develop networks and connections around the country; arguably helped the Democrats have a very good 2008. Hell, given that Clinton is <i>so</i> well known, subject to national attacks for almost thirty years, it probably wouldn't matter if Sanders did go negative.<br />
<br />
Another thing that amuses me about this election is how lopsided it is. At the halfway point, Clinton has won an overwhelming 57.8% of the delegates. And yet, if we group the states into different geographical regions, we see the following delegate totals<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#3" name="top3"><sup>3</sup></a>:<br />
<br />
<style type="text/css">.nobrtable br { display: none }</style>
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<div class="nobrtable">
<table border="2" bordercolor="#0033FF" cellpadding="3" cellspacing="3" style="background-color: #99ffff; width: 100%px;">
<tbody>
<tr>
<th style="text-align: center;">Region</th>
<th style="text-align: center;">Clinton</th>
<th style="text-align: center;">Sanders</th>
</tr>
<tr>
<td style="text-align: center;">North-East</td>
<td style="text-align: center;">64</td>
<td style="text-align: center;">92</td>
</tr>
<tr>
<td style="text-align: center;">Mid-West</td>
<td style="text-align: center;">331</td>
<td style="text-align: center;">348</td>
</tr>
<tr>
<td style="text-align: center;">South</td>
<td style="text-align: center;">719</td>
<td style="text-align: center;">351</td>
</tr>
<tr>
<td style="text-align: center;">West</td>
<td style="text-align: center;">48</td>
<td style="text-align: center;">53</td>
</tr>
<tr>
<td style="text-align: center;">Other</td>
<td style="text-align: center;">12</td>
<td style="text-align: center;">13</td>
</tr>
</tbody></table>
</div>
<br />
We see that Clinton is actually <i>losing</i> in all regions other than the South! Her lead is a combination of winning the South heavily, and the over-representation of Southern states so far. Indeed, the South makes 53% of delegates voted on so far compared to only 32% in total.<br />
<br />
This is not to try and argue that Clinton is really losing. The simplest extrapolation of the above, assuming the ratios in each region remains the same, would lead to Clinton 2139 vs Sanders 1912, a 5.5% margin in delegates. But it's the kind of thing that definitely surprised me when I first realised it.<br />
<br />
The last thing I want to note relates to the question of a long primary. Because unless Sanders drops out or primary voters start to coalesce around Clinton in huge numbers, the race is not going to be over till 7th June, when six states including California vote. To win a clear majority before then, Clinton would have to pick up at least 65% of delegates from here on. What makes that unlikely is that in the Democratic race, <i>every</i> state awards its delegates proportionally. So if the Democratic party isn't happy, they really only have themselves to blame.<br />
<br />
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<a href="https://www.blogger.com/null" name="1"><b>1 </b></a>Throughout this post I'm using the projections of the <a href="http://www.thegreenpapers.com/P16/events.phtml?s=c">Green Papers</a>. I remember them being the best 8 years ago.<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#top1"><sup>↩</sup></a>
<br />
<a href="https://www.blogger.com/null" name="2"><b>2 </b></a> I saw plenty of people online say he'd lost when we failed to win Iowa, almost too eager to proclaim the death of his campaign.<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#top2"><sup>↩</sup></a>
<br />
<a href="https://www.blogger.com/null" name="3"><b>3 </b></a>Here I use US Census Bureau <a href="https://en.wikipedia.org/wiki/United_States_Census_Bureau#Census_regions_and_divisions">definitions</a>.<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#top3"><sup>↩</sup></a>
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Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-5977550140336431722016-03-21T02:41:00.000+11:002016-03-21T02:41:51.174+11:00The Iain Duncan Smith Saga<div dir="ltr" style="text-align: left;" trbidi="on">
The fallout of the budget took an unexpected turn on Friday, when work and pensions secretary (and former leader of the opposition) Iain Duncan Smith <a href="http://www.theguardian.com/politics/2016/mar/18/iain-duncan-smith-resigns-from-cabinet-over-disability-cuts">resigned</a>. His stated reasons were in opposition to the continued cuts to social services that have been criticised by many, including me. The result has been a <a href="http://www.bbc.com/news/uk-politics-35855616">vicious exchange</a> between Duncan Smith and George Osbourne that, given the former's tenure as party leader, reminds me of the famous quote that being attacked by <a href="https://en.wikipedia.org/wiki/Geoffrey_Howe">Geoffrey Howe</a> was "like being savaged by a dead sheep".<br />
<br />
Of course, Howe ended up bringing Thatcher down, which makes that an interesting comparison.<br />
<br />
The other thing of note is whether Duncan Smith is being entirely honest. <a href="http://www.theguardian.com/politics/2016/mar/20/iain-duncan-smith-resigned-eu-not-benefit-cuts-altmann">Some have suggested</a> that this is just a front, and his real disagreement is over Europe. And it's not as if he's been opposed to cuts before, although the decision to spend <a href="https://www.nao.org.uk/report/contracted-out-health-and-disability-assessments/">£1.6 <i>billion</i></a> in corporate administration, to save £1 billion in welfare payments, suggests that perhaps he does object to having to spend less.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-36779039428893022532016-03-21T02:10:00.001+11:002016-03-21T02:10:53.315+11:00Moriond and 750 GeV Diphotons<div dir="ltr" style="text-align: left;" trbidi="on">
So the big news of the week is that we've just had <a href="https://indico.in2p3.fr/event/12279/">Moriond</a>. CMS presented a <a href="https://indico.in2p3.fr/event/12279/session/12/contribution/218/material/slides/0.pdf">reanalysis</a> of their 13 TeV data on the diphoton excess; this included some additional data taken with zero magnetic field, equivalent to a 10% improvement. I heard that ATLAS pulled out of presenting a new analysis, though that's not obvious from their <a href="https://indico.in2p3.fr/event/12279/session/12/contribution/163/material/slides/1.pdf">talk</a>. CMS's new result, including 8 TeV data, has a 3.4σ local significance for the excess (up from about 2.4σ). The rumour I heard for ATLAS was 4.7σ local!! Which may be why the pulled out, that they got a significance too high for them to put faith in it.<br />
<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://3.bp.blogspot.com/-rnCGNVYAJoI/Vu68_iNc5hI/AAAAAAAAAeg/Qz-UcRO3eR4ErsgxXCHC-o7PV39uP3Icg/s1600/Screen%2BShot%2B2016-03-21%2Bat%2B12.08.12%2BAM.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" height="312" src="https://3.bp.blogspot.com/-rnCGNVYAJoI/Vu68_iNc5hI/AAAAAAAAAeg/Qz-UcRO3eR4ErsgxXCHC-o7PV39uP3Icg/s320/Screen%2BShot%2B2016-03-21%2Bat%2B12.08.12%2BAM.png" width="320" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">ATLAS (red) and CMS (blue) results, from <a href="https://indico.in2p3.fr/event/12279/session/12/contribution/110/material/slides/1.pdf">Strumia's</a> Moriond talk</td></tr>
</tbody></table>
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<a name='more'></a><br />
The LHC is still in winter shut-down. We won't <i>really</i> know if this is something knew, or just a cruel quirk in statistics, till the Summer. On the other hand, the experimental
collaborations have not been able to find anything wrong with what
they've done so far. But on the original hand, at least half the reason people are so excited about this is because we don't have anything else to latch on to. This is the best year to make a discovery at the LHC. Given how long it will take for the next generation machine to turn on, this is the last chance for some people to see a discovery in their career.<br />
<br />
Personally I remain somewhat sceptical. Partly that's my own personality, but even in my relatively short career I've seen a lot of potentially exciting things go away with more data. Also, this is not something anyone was predicting, which is both a good and a bad thing. The good is that it's a surprise, and that's how we learn. Plus it means I'm not horridly disadvantaged against the people who spent their lives studying three-loop SUSY or whatever. However, from a Bayesian perspective, a surprise corresponds to a lower prior: being unexpected makes it less likely.<br />
<br />
That said, I've written one paper and am writing another on the excess<i>.</i> There's one thing I'm not sceptical about, which is that this is a citation magnet. <br />
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Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-26121750455421697672016-03-18T21:10:00.002+11:002016-03-18T21:10:26.989+11:00Corbyn's Labour Ahead in the Polls<div dir="ltr" style="text-align: left;" trbidi="on">
For the first time since Jeremy Corbyn's surprise victory in the Labour leadership contest, an opinion poll has them <a href="http://www.independent.co.uk/news/uk/politics/new-poll-puts-labour-ahead-of-tories-for-first-time-since-jeremy-corbyn-became-leader-a6937926.html">above the Tories</a>:<br />
<blockquote class="tr_bq">
<br />
A new poll has put Labour ahead of the Conservatives for the first time since Jeremy Corbyn was elected leader. </blockquote>
<blockquote class="tr_bq">
...</blockquote>
<blockquote class="tr_bq">
A recent poll by ICM
had put the Conservatives and Labour level on 36 per cent, but some had
thought this might have just been a one-off, freak result.</blockquote>
Sadly, as someone who likes Corbyn more than not, this is probably a feature of disaffection with the current government more than anything else. The recent <a href="http://perfectpuddle.blogspot.kr/2016/03/budget-time.html">Budget announcement</a> probably exacerbated discontent with the economy and government cuts. And we still see large discontent with both parties, with a third of the electorate preferring someone else, most notably UKIP (spit).<br />
<a name='more'></a><br />
Still, it is something. As the most left-wing leader of a major UK party in several decades, Corbyn has been attacked a lot by the British press<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#1" name="top1"><sup>1</sup></a>
. After all, he wants to do dangerous things like undo the run away success that is the privatisation of the railways, or discuss if nuclear weapons are worth the price. Or, most damningly of all, raise taxes on ordinary people who just happen to be rich enough to own newspapers. To be ahead despite this shows that there is some hope the British electorate can, on occasion, do the right thing.<br />
<br />
On a slightly different note, apparently one problem the Tories have had is the current debate over the EU.<br />
<blockquote class="tr_bq">
Anthony Wells, YouGov’s director, said the Conservatives’ “Euro squabbles” were “hurting the party’s image”. </blockquote>
<blockquote class="tr_bq">
When its poll was published on Monday, ICM warned it might just be a “rogue” result. But it also said the Tories’ splits over the European Union could be hurting its level of support.</blockquote>
This just baffles me. It's a sign of weakness that not all members of a political party agree on something? It's not that I doubt people might actually think this way. I just don't know why. But then, I tend to think that debate is a sign of strength, respectful disagreement a sign of healthy society and that complex problems usually don't have simple answers; opinions that I suspect the majority don't share.<br />
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<span class="Apple-style-span" style="font-size: x-small;">
<a href="https://www.blogger.com/null" name="1"><b>1 </b></a>And to think I once smugly looked down on the American news media.<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#top1"><sup>↩</sup></a>
</span>
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Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-61186818267942172912016-03-18T01:39:00.003+11:002016-03-18T01:39:54.872+11:00Budget Time<div dir="ltr" style="text-align: left;" trbidi="on">
Let's talk a little about British politics for a change. The BBC decided the <a href="http://www.bbc.com/news/uk-politics-35813973">headline for their story</a> on the new budget would be about the surprise inclusion of a "sugar tax" on soft drinks. In a clear example of its left-wing bias, news that welfare spending would have to be cut to reduce deficits, but that there was certainly money to cut corporation tax and the top rate of capital gains, was buried in the middle of the article.<br />
<br />
Of course, it's hard to judge what the impact of the budget will be on social inequality since last year the government <a href="http://www.theguardian.com/uk-news/2016/mar/14/the-chancellor-must-be-honest-about-the-budgets-implications">decided to stop including that information</a>. But I'm sure there's no nefarious intent. Why, neither Cameron <i>nor</i> Osborne has a mustache to twirl! Plus, as the Hufington Post <a href="http://www.huffingtonpost.co.uk/entry/budget-2016-george-osborne_uk_56e97af0e4b096ed3adcb0a0?jmyhudsq6ohxxyldi">pointed out</a>, cutting corporation tax is a major example of fixing inequality, allowing <i>all</i> companies to pay closer to what Google does.<br />
<br />
<a name='more'></a><br />
On a more serious note, when the Tories first came into power, they set about reducing the deficit with cuts across the board, including the military, and even temporary tax increases. Of course, they had the "moderation" of the Lib Dem coalition. But also, when the economy remained sluggish after the first couple of years in office, Osbourne engaged in a more expansionary financial policy with quantitative easing. And, surprise surprise, the economy actually improved.<br />
<br />
Cutting the deficit is one of those things that sounds like an automatic good, which is why politicians who manage it like to boast about it. But this is largely based on intuition from individual finances, while governments are a different beast. Especially for stable developed nations like the UK, there is a guaranteed source of income in taxes, while most individuals must worry about losing their job. Plus, countries are long-lived things, many individual lifetimes. All of this makes it easy for governments to borrow money cheaply. Especially when interest rates and inflation are low, there's no real urgency to cut spending. Sure, sooner or later it has to be done, but why now? <br />
<br />
In truth, the obsession with the deficit clearly goes beyond economics. Osbourne wants to present himself as the economic mastermind behind the recovery in governmeny finances after the Brown years. Presenting a zero deficit is clearly something he thinks will help him win the leadership of the Conservative party after Cameron. Indeed, he's rather staked his reputation on it, so that he pretty much must do it no matter what the best course of action would be. In this sense, I'm reminded of Brown, who made a big deal out of keeping the debt below a completely arbitrary percentage of GDP... from whence came PFI, selling off the gold reserves and all the other fun things we remember him for. Because, to do otherwise, would have been to lose his chance to move from Number 11 to Number 10.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-46626458679904214552016-03-17T00:09:00.003+11:002016-03-17T00:09:48.803+11:00Aftermath<div dir="ltr" style="text-align: left;" trbidi="on">
<div dir="ltr" style="text-align: left;" trbidi="on">
Well, I made some comments before the primary elections, so it's probably worth saying a few words about the aftermath.<br />
<a name='more'></a><br />
Starting with the Democratic side, a clean sweep for Clinton puts a lot of pressure on Sanders. We're still waiting on the last few delegates to be projected, but it looks like Clinton will have maintained, even expanded upon a 16% lead in pledged delegates. Since we're now pretty much at the half-way point, Sanders would have to start winning like never before to catch up. While the remaining states are more favourable to Sanders, and in particular there are only a couple of southern states left, it's hard to see how he wins without some kind of external factor, such as Clinton suffering a medical crises leaving her unable to continue.<br />
<br />
Although, with the most current numbers there are, it seems that Clinton is still behind everywhere except the South in terms of pledged delegates. There are still a lot of delegates to be assigned, so that might change. If not, I might come back to this later in the week.<br />
<br />
On the Republican side, the big news is obviously Rubio dropping out after being heavily defeated by Trump in his home state of Florida. With Kasich essentially running for Vice President<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#1" name="top1"><sup>1</sup></a>
, the two remaining choices are the fascist and the theocrat. Not that either Rubio <i>or</i> Kasich are really what I'd call moderate, but in comparison they definitely tick the "less evil" box.<br />
<br />
The "good" news is that Trump did not take Ohio, which slows him down a lot. He's picked up on 44% of the delegates so far, and needs 54% of the remainder to win a majority of pledged delegates. With most remaining states using winner-takes-all either for all their delegates, or by congressional district, that's a lot more possible than on the Democratic side. Plus, it's basically down to a two horse race.<br />
<br />
However, a majority of <i>all</i> delegates on the Republican side would require Trump to get 60% of the remaining pledged cohort. That's much harder, though still not impossible. Plus, if things are close stopping him would require a unified opposing front. If Trump gets a majority of the pledged delegates, there's a serious danger for the Republican party if they give the nomination to someone else; they might decide it's better to stick with him, lose the election, and then try to rebuild later. After all, there's no precedence for giving power to a far-right politician temporarily and things going bad, are there?<br />
<br />
And having Godwinned, the post is over.</div>
<hr width="80%" />
<span class="Apple-style-span" style="font-size: x-small;">
<a href="https://www.blogger.com/null" name="1"><b>1 </b></a>Indeed, he can no longer win a majority of delegates.<a href="https://www.blogger.com/blogger.g?blogID=5761489922821739096#top1"><sup>↩</sup></a>
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Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0tag:blogger.com,1999:blog-5761489922821739096.post-74447396854757355262016-03-16T01:16:00.002+11:002016-03-16T01:16:32.935+11:00Sort of OK Tuesday<div dir="ltr" style="text-align: left;" trbidi="on">
Like many non-Americans, I've been watching the current US primaries with a certain horror; I can't bear to watch, yet neither can I look away. The Republican party has been steadfastly advancing in the fields of xenophobia, bigotry and bullying, but it still seems barely credible that they might nominate an actual fascist. Although, when you look at the other candidates, and especially current runner-up Ted Cruz, they're not exactly any more appealing.<br />
<br />
<a name='more'></a><br /><br />
The "good" news, such as it is, is that Trump remains below the 50% margin in terms of delegates. But today's elections could change that, with winner-takes-all states in Florida and Ohio offering the potential to settle the election as a contest ... or keep things going all the way to the convention. There have been reports of cooperation between the non-Trump candidates, with Rubio telling his supporters to vote for Kasich in Ohio and getting support in Florida. We'll have to wait and see what happens.<br />
<br />
I know many on the left are excited about the prospect of Trump being nominated, seeing him as easy pickings in the general election. I'm not one of them. Aside from the affects a Trump candidacy would have on the nature of the political discourse, anything could happen during the campaign to swing things. After all, Trump was never supposed to be a serious contender for the Republican ticket. Sooner or later the Republicans will win the White House again, and for the sake of the world not to mention my American friends, I'd prefer them to do it with someone who isn't a pantomime villain.<br />
<br />
On the Democratic side, today is also interesting. Clinton has a fairly commanding lead, even without superdelegates. After Nevada, I marked today as the day the contest would end. But then Sanders won in Michigan, and things looked a lot more interesting. I also discovered the surprising result that despite Clinton's heavy lead, she is actually behind in each of the North-East, Mid-West and West. In terms of pledged delegates, she only leads in the South, and the reason her lead is so large is in part due to the fact that southern states have been over-represented in the primary so far.<br />
<br />
Of course, strong wins in Illinois, Ohio and/or Missouri could change that today. My initial prediction still seems the most likely outcome. But one or two more upsets for the Sanders campaign would be enough to keep things going, at least as far as New York at the end of April. As would surprise no one who knows me, I prefer Sanders, so I see this as a good possibility. Clinton, aside from her recent "gaffe" over Nancy Reagan, strikes me as someone who'd be much like Obama: some good, but a continuation of the NSA spying on everyone, drones bombing brown-skinned <strike>people and hospitals</strike> terrorists, and economic policies designed to favour the wealthy over the poor. In short, very much a lesser-of-two-evils kind of thing.</div>
Andyhttp://www.blogger.com/profile/03294858693736147605noreply@blogger.com0