Saturday, 31 August 2013

SUSY 2013 Live Blog: Final Session

We end with some review and summary talks.

10:30am: John Ellis, "Outlook for supersymmetry"

A clue about John's opinion: his t-shirt has "MSSM" written on it.

I recognise the opening slide from Cairns.

"Is outlook for SUSY black?  Bullshit!"  Claims Higgs observations provide more evidence for SUSY, not less.

The LHC paradox: a light Higgs plus nothing else?  If there is something else light, why haven't we seen it?  If there is nothing light, is the Higgs unnatural?  There has been a high mortality rate among theories, but not SUSY.  Comment on split-/High scale-/etc. SUSY, "If you can't say something good, say nothing".

SUSY anywhere is better than SUSY nowhere.

Mh-Mt close to stability bound.  Instability sets in at 1010-1013 GeV.  Claim that we do need to fix this.  Natural way to do this is to add a new stop-like scalar, but that only brings more fine-tuning and stability issues.  These are best solved with a Higgsino.

"Anybody sensible would say that the Higgs that has been observed is the lightest supersymmetric Higgs."

Various data that has to go into global fits.  Big question is g-2.  Is there low-scale SUSY, as this suggests?

2012 data does not rule out as much of CMSSM parameter space as you might expect.  Even best-fit point of pre-2012 is still fine.  CMSSM has two preferred regions now, one with gluinos just above the exclusion limits and another at 4-5 TeV; latter is probably too heavy for LHC.  Stops have similar masses.  Stau is NLSP, can be as light as several hundred GeV.  Can be long-lived; small mass splitting with LSP (less than tau mass) is preferred in global fits.

Planck evidence: simple SUSY inflationary models fit the constraints, especially no-scale supergravity.

DM DD: Probe SUSY parameter space by 2020.

DM positrons: probably astrophysics, but can use smooth spectra to place constraints.

What's next?  A Higgs factory; LHC upgrades?  ILC?  CLIC?  TLEP?  TLEP could test SUSY predictions in deviations of Higgs couplings.  Most alternatives could not.  TLEP could, like LEP, be later replaced with hadronic collider (100 TeV).

Note: we had to wait 48 years for the Higgs.  We have only been waiting 40 years for SUSY—keep the faith!

11:10 am: Nima Arkani-Hamed, "Supersymmetry 2033"

The title is based on the fact that this is the 21st SUSY conference, so look 20 years back and 20 years forward; plus, of course, the fact the LHC is giving us results and will change things.

The talk is a motivation for a 100 TeV pp machine.  It is an obvious direction.

Precisely what we need to do depends on what is seen at LHC 13/14.  But "every scenario I can envisage will need a 100 TeV machine."  Not obvious it would have been, e.g. had we found light SUSY.

A lot of technically interesting questions, but focus on the physics question.

1. The ultimate fate of naturalness.  Higgs discovery is crucial; our vacuum is qualitatively different to a random condensed matter system.  In none of our studies of EFTs in the lab do we see a light scalar without deliberate external fine-tuning.

Naturalness has been invoked before the Higgs, and every time it worked.  They are: the classical self-energy of the electron, infinite.  Leads to models based on a cut-off; models where wrong, but there was new physics at that scale (QM); in fact, even earlier than it needed to!  (Due to weak EM coupling.)

Second case is the pion; quadratic QED corrections to the pion mass.  Again, quadratically divergent contributions cut-off by the rho, again came in earlier than it needed to.

Third is Kaon mixing.

It may well have worked before, but where is everybody?  This is not a new problem; there has been a tension from the beginning because of the SM approximate symmetries that cannot be broken at the TeV scale.  Not problems, opportunities!

Naturalness has failed dramatically before.  Aristarchos's model of the solar system was unnatural, since the distant stars had to be ridiculously far away!  More recently, we have nuclear physics; consider the small deuteron binding energy, or the fact that two neutrons are not bound by a 1% factor.  Related to up/down quark masses?  And, of course, the cosmological constant problem.

You can use history to argue either way.  Worth keeping that in mind.

The question of if the Higgs scale is natural is then a deep, structural question about the foundation of fundamenal physics.

a. What if LHC sees nothing else.  Tuning of 1% in Higgs mass.  Is that convincing to kill naturalness?  Well, we have seen this kind of tuning before (neutrons!) and has not forced us to make a radical departure in our philosophy.

We can only properly address this question by going to higher energies.  If we find something, we end the discussion.  If we find nothing, we get a quadratic gain in the tuning with the energy of the machine!  So a 100 TeV collider will push the tuning down to 10-4, hundred times worse than anything seen in particle physics before.  Much much harder to dismiss this.

b. Fine-tuned theories could exist that are not anthropically motivated.  Example: find a TeV-scale Higgs, nothing else up to 100 TeV.  Now have worse tuning, and no anthropic reason!  Force us to really reexamine our entire point of view.

c. If we unlucky and NP is just outside of LHC, obviously 100 TeV machine will find it.  Also, consider split scenarios; minimal picture prefers gluino below about 20 TeV, so should be found.  Also, if found and they decay in the detector at all, that tells us new scale not too far away.

d. What if LHC discovers (relatively) natural spectrum?  Will be too heavy to study at a low-energy lepton collider, while coloured particles will not be produced in large numbers of LHC.  Plus, if we do see a natural spectrum then a number of particles will be too heavy to see at the LHC.

2. Robust probe of few TeV electroweak particles, e.g. WIMPs.  Impossible at LHC.

3. Collider flavour physics.  Can not have theory of flavour at 1 TeV, can at 30-40 TeV.  (e.g. RS).  Not guaranteed, by any means, just possible.  Tops produced in large numbers.  Various low-energy probes of CP-violation, EDM etc; if they find anything, the scale must be in the 10s or 100s of TeV.

Summary: "The scientific questions at stake in our field are the deepest ones we have encountered in 50 years."  Our ambition should match the size of the question.  The time to start thinking about this is now.

And with that, SUSY is effectively over.  We have one final talk telling us about SUSY 2014, which will be in Manchester next July.  However, I don't think I need say much about this.

I will write my own thoughts on the conference as a whole some point in the next few days.  First, I'm indulging in a little sightseeing this weekend, and I also need to write a seminar talk by Thursday!

SUSY 2013 Live Blog: Day Six

The final day of SUSY 2013 is, like most conferences, only a half-day.  The two sessions cleanly split into a pre-coffee flavour session, followed by a post-coffee wrap-up.  I'll be honest, the latter is more attractive to me (plus talks from John Ellis and Nima (again)).  But I won't dismiss this first session yet.

Between this being the last day of the conference—so people are starting to leave—and the conference banquet last night, the auditorium is strikingly empty this morning.  Still, unlike some conferences *cough*Pheno 2013*cough* SUSY at least got it right in putting the banquet after all the parallel sessions had finished.

SUSY 2013 Live Blog: Day Five Session Four

So It Has Come To This.  The last parallel session of SUSY 2013.  And what better place to sit than the SUSY Phenomenology session.  We have four talks to bring this part of the conference to a close.

Friday, 30 August 2013

SUSY 2013 Live Blog: Day Five Session Three

We start the last afternoon session of the conference.  I've decided to start out in the Higgs session again.  As I noted last time I was here, this session is heavily subscribed, so we have six fifteen minute talks before the coffee break.  I hope that won't be too much.

SUSY 2013 Live Blog: Day Five Session Two

As usual, we follow the first round of experimental talks with some post-coffee theory.

SUSY 2013 Live Blog: Day Five

We've reached the last ful day of SUSY 2013.  We start the morning with another pair of LHC talks, this times on the so-called exotic searches.  As this is a SUSY conference, they only get 35 minutes, unlike the 45 minutes the SUSY searches got.  Of course, like the SUSY searches we know going in the final statement; nothing has been found.

Montana Judge ...

Do I need to complete that title?  Anyway, a Montana Judge has shown how sexism is dead by handing a one month sentence to a man who raped a 14 year old, saying she was responsible.
A Montana judge who said a 14-year-old rape victim was "as much in control of the situation" as the man who assaulted her is under pressure to resign.
Montana Judge Todd Baugh also said the girl was "older than her chronological age", as he handed the teacher who assaulted her a month in prison.
The mother of the victim, who took her own life three years ago while the case was pending, is furious.
Now if you'll excuse me, I need to go throw up.

SUSY 2013 Live Blog: Day Four, Session Four

Anyone reading this currently will realise I skipped this session.  My own talk was during it, so I wanted to focus on that instead.  I meant to post something to that effect before the session started, but I ended up without time.  My talk went okay, I think, though my throat was very dry by the end of it.

Thursday, 29 August 2013

SUSY 2013 Live Bog: Day Four, Session Three

I've decided to spend the afternoon sessions attending the non-SUSY talks.  Obviously, that's the place to be at a conference called Supersymmetry.

SUSY 2013 Live Blog: Day Four Session Two

The post-coffee break session returns to more very theoretical topics.

SUSY 2013 Live Blog: Day Four

We return to a full day of talks at SUSY.  The morning's plenary sessions open with a talk on dark matter and another on cosmology.

Wednesday, 28 August 2013

SUSY 2013 Day Three

Wednesday is one of two half-days here at SUSY, the other being Saturday.  As such we have only plenary talks this morning, including the two longest talks of the conference.  These are CMS and ATLAS talks on SUSY searches, running to 45 minutes each.

Unfortunately, I won't be able to live blog these as I have some urgent work to take care of.  Still, I can summarise the talks quite simply: nothing has been found despite a lot of clever work, and the limits are getting pretty strong.

SUSY 2013 Live Blog: Day Two Session 4

For the last session of the day I've returned to the SUSY phenomenology parallel talks.

Tuesday, 27 August 2013

SUSY 2013 Live Blog: Day Two Session Three

For the first parallel session of the day I'm in the dark matter/cosmology session.

SUSY 2013 Live Blog: Day Two Session Two

With the first round of experimental talks complete, now we have some theory to discuss the implications.

SUSY 2013 Live Blog: Day Two

The second day of SUSY starts with a pair of experimental talks on the Higgs results.

SUSY 2013 Live Blog: Day 1 Session 4

For the final SUSY 2013 session of the day I'm at the Higgs session.  To noone's surprise, this is by far the most over-subscribed group of sessions.

Monday, 26 August 2013

SUSY 2013 Live Blog: Day 1 Session 3

We progress to the first parallel session of the conference.  I've decided to attend the SUSY phenomenology talks, which in this case appears to actually be SUSY experimental results.  So, four talks saying variations of "we find no signal".  Curiously, we have three CMS talks to only one ATLAS talk.

SUSY 2013 Live Blog: Day 1 Session 2

Two much-needed cups of coffee later, we continue the morning plenary sessions with three talks and no obvious theme that I can see.

SUSY 2013 Live Blog: Day 1

Another conference, and because it went well last time I'm going to continue with live blogging as a proxy for taking notes.  This time it's Supersymmetry 2013, held in Trieste.  Travel here was pretty awful, but I might put my complaints into a different post if I feel like it.  (Protip: don't fly with Alitalia.)

Interestingly, we start with a talk not about LHC results, the Higgs or even SUSY in general.  The first talk after the introduction is Stefano Profumo on Dark Matter.

Thursday, 22 August 2013

Busy Busy Busy

One problem with writing a blog as a scientist is that I spend a good chunk of my time writing other stuff.  In particular, I'm currently writing several talks for SUSY 2013 next week and some seminars in the following weeks.  Much like the problem I have with reading these days, after a hard day's writing I'm not too inclined to spend an hour or more constructing a post here.

Still, I should have the main things finished soon, and I'll likely be live blogging SUSY next week as well.  So that should help me post more regularly again.  Also, as the main game I'll have with me will be ToME, I might finally get around to writing a review of it.

Friday, 16 August 2013

A Christian Talks About Homosexuality

I've often linked to stories with religious people espousing homophobia and other bigotries.  So it's probably time for me to link to something a bit different:
Christians in Britain and the US who claim that they are persecuted should "grow up" and not exaggerate what amounts to feeling "mildly uncomfortable", according to Rowan Williams, who last year stepped down as archbishop of Canterbury after an often turbulent decade.
"When you've had any contact with real persecuted minorities you learn to use the word very chastely," he said. "Persecution is not being made to feel mildly uncomfortable. 'For goodness sake, grow up,' I want to say."
Of course, I have other problems with Williams—even some of the stuff he's quoted as saying within that article—but it's nice to see a cleric call out this type of behaviour.

Airport Security Does Something Useful

This story has me conflicted.
Teenage girls who fear they are being taken abroad to enter into a forced marriage are using a simple trick to escape: hiding a spoon or any other metal object in their underwear to set off the metal detector at the airport and avoid the flight at the last minute.
On the one hand, it's a story of success: these girls are avoiding a nasty fate with a simple but ingenious idea.  On the other, they shouldn't have to.

The idea is apparently being promoted by charity Karma Nirvana, that I previously wasn't aware of.  According to the news article linked above,
Its founder, Jasvinder Sanghera, was disowned by her Sikh family at the age of 16 after she refused to marry a man in India. She set up the charity in 1993, when she was 27.
And from the charity's website,
If you’re here to tell us that we can please all cultures without causing the slightest bit of offence - well, frankly, you’ve come to the wrong place.
I'll be in the UK next month, so it should be a good time for me to send some money their way.

Tuesday, 13 August 2013

Revisiting Pluto

Planetary astronomy is usually outside my sphere of interest, but I came across a paper last week that defied that trend.  As the title suggests, it returns to the decision in 2006 to reclassify Pluto as not being a planet.  To summarise for those who don't remember, the traditional set of nine planets was threatened by two consequences of modern telescopes.  First was the discovery of increasing numbers of planet-like bodies, including at least one as large as Pluto itself; second the realisation that Pluto was smaller than once thought, indeed likely smaller than Earth's moon.

Monday, 12 August 2013


Quote from a news article about Gibraltar:
Spain also said it was considering taking the dispute to the UN Security Council, where it could seek the support of Argentina.
A Spanish government spokesman told the BBC that although the Falkland Islands - over which Britain went to war with Argentina - and Gibraltar were different issues, there were similarities between the two disputes.
The similarity, of course, is that the populations in both territories overwhelmingly prefer the status quo, and have repeatedly voted to that fact.  Self-determination; what's that?

Saturday, 10 August 2013

Little is Cute

I've previously talked on this blog about supersymmetry and extra dimensions.  Another class of models for new physics is the Little Higgs (LH) family.  While these models have faded out of primary focus in recent years, even before the LHC turned on, I always have a soft spot for them as they were the subject of my early research as a grad student.  So I tend to read, browse, or at least skim new work in this area, and that's the subject of this post: a paper from the end of July on new dark matter constraints in LH models.

Tuesday, 6 August 2013

The High Ground

Browsing the news, I came across this little article:
The US has criticised a new internet decree in Vietnam that would restrict online users from discussing current affairs.
The law, announced last week and due to come into force in September, says social media should only be used for "[exchanging] personal information".
As we all know, the correct course of action is to allow people to discuss things online, but record all communications.  That way, when you need to lock someone up for being a troublemaker, you'll have so much evidence there must be something you twist into a case against them.

England Retain Ashes

Sometimes, it's good to be a Brit living in Australia.

Monday, 5 August 2013

No Winos

Oh yes, I have a blog.

Yes, it's been a while since I've written anything here.  There's a number of reasons, but the main one is simply lack of time.  Not exactly dramatic, but sometimes that's the way it is.  I'm now hopeful that I can make at least semi-regular updates again.

I'll start with an overview of a couple of recent research papers, that came out in the same week with very similar results.  They relate to the Winos of the title, which is pronounced "weeno", not "weye-no".  Winos are particles that show up in supersymmetric theories (hence the suffix -ino) and are partners of the W and Z bosons.  They are also one of the possible dark matter particles in these theories.  The thrust of the two papers I'm considering, "Wino Dark Matter Under Siege" and "In Wino Veritas", is that these are ruled out in that role.