Thursday, 28 May 2015

Planck 2015 Liveblog: Day Four, Session Three

I skipped the morning sessions with almost no regret.  (Actually, there was a talk from LHCb among all the string theory, that might have been interesting to attend.)  Thankfully, there are two talks in the last plenary session of the day that should be interesting.

3:00 pm: "Signatures of Supersymmetry with Underabundance of Neutralino Dark Matter", S Pokorski

Unfortunately, I've missed the start of this talk taking care of some other business.

Expressions for pure Higgsino/Wino relic densities are lower bounds in much of parameter space.  Adding Bino component will reduce annihilation cross sections and increase relic density.  (Assuming thermal RD, of course.)

Exclusions for models where neutralino makes only part of DM are weaker for the obvious reasons.  But there remains some sensitivity in direct detection experiments.  Indeed, LUX already excludes Wino-Higgsinos which only make up a few percent of DM (up to a few hundred GeV in mass).

A related consequence is that for these models, the neutralino-chargino splitting is required to be smaller than 50 GeV, reduced to 10 GeV from Xenon 1T.  This has immediate collider implications.

It's hard to judge these statements as, having missed the start of the talk, I don't know what the exact assumptions here are.  Is this profound or fairly simple?  Once again, I am angered by the lack of the slides being online.

Discussion of the implications in terms of mono-X and disappearing track searches.

Conclusion is that (for heavy sfermions) LHC plus direct detection will efficiently explore the parameter space.

Do LUX exclusions shown give upper bound on neutralino mass?  Yes/no, upper bound is relic density.
What about non-SM Higgses?  Also taken heavy.
Relax assumptions about sfermions, especially sleptons?  Yes, preliminary work in progress.

How many fucking phones have gone off in this talk alone?  Fucking rude assholes.

3:30 pm: "Towards a Phenomenology for the Non-supersymmetric Heterotic String", S Abel

This is a less interesting title, but I might give the talk a try.

The motivating question: can we get the (non-supersymmetric) SM from UV-complete string theory?  (Avoid EFT.)

Getting non-SUSY theory from SUSY string is well-understood, dates back to late '80s.  Take E8xE8 perturbative heterotic string.  Can define a partition function.  Find that UV divergences go away, only IR divergences remain.  Complication is that integrals get contributions from non-physical (tachyonic) states.

4:00 pm: "SUSY Dark Matter: Lessons from and for the early Universe", Leszek Roszkowski

 The extra word in the title that wasn't on the schedule has made this talk a lot less exciting.  I have also had too little coffee today.  Yeah, this talk looks like it is more SUSY than DM.

"SUSY cannot be experimentally ruled out".  Paging Dr Popper...

We've made a peculiar digression into statistics, Bayesian vs Frequentist.

Did something, CMSSM? Higgsino DM so probed in DD, not LHC.

Fine tuning doesn't matter because I said so.

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