The big yearly SUSY conference, SUSY 2013 has been going on in Trieste this past week. From the experimentalists, the news is just stronger limits: no hint of SUSY anywhere in the LHC data. From the theorists, the reaction to this news has been pretty consistent: despite what people say, not a problem.
According to John Ellis, everything is fine, with MSSM SUSY preference for a Higgs below 130 GeV vindicated and successful SUSY predictions for the Higgs couplings (that they should be the same as if there were no SUSY). According to Ellis, we just need to be patient, and he has CMSSM fits preferring 2 TeV gluinos.
However, if you look at Savas Dimopoulos’s talk the MSSM gets a grade of D-. He argues that the LHC has shown us that the answer is the Multiverse, and that split SUSY with its fine-tuning gets a grade of A. The grade inflation in particle physics is pretty dramatic: you now can get an A without your theory having the slightest bit of experimental evidence.
Nima Arkani-Hamed’s talk was about SUSY in 2033, which in his vision will be pretty much the same as SUSY in 2010. Remember all those things the LHC was supposed to find but didn’t? Well, now the argument is that they’re really there, but we will need a 100 TeV collider to see them. If all goes well, in 2033 such a machine will be under construction, and SUSY 2033 could feature all the SUSY 2010 talks retreaded, with 1 TeV gluinos moved up to 10 TeV.
One of Arkani-Hamed’s slides
makes me worry that the LHC results have caused him to begin to lose his marbles. He claims that if one doesn’t see new physics like SUSY at the 100 TeV machine, in his view
this would be 100 times more shocking and dramatic than
nonothing but Higgs at the LHC
[I initially misread and misquoted this, my apologies. The claim was not that no BSM at 100 TeV would be 100 times more shocking than no Higgs at the LHC, but that it would be 100 times more shocking than no BSM at the LHC. So, the usual sort of over-the-top exaggeration, but not crazy.]
Even wilder claims came form Gordon Kane in his talk, where we’re told that particle theorists giving “negative” talks because of the LHC results have:
no knowledge of LHC physics, Higgs physics, supersymmetry, phenomenology, etc.
According to Kane, we not only have seen the tip of the iceberg of a unified string/M-theory, but actually have the whole iceberg. The ingredients are all in place for what he sees as a similar experience to the 3 year period in the 1970s when the Standard Model emerged and was experimentally vindicated.
On a more positive note, at the conference production of compactified Calabi-Yaus was finally conclusively demonstrated.
Update: Nathaniel Craig has some recent lectures on The State of Supersymmetry after Run I of the LHC. The emphasis is on examining the consequences of failure of pre-LHC assumptions about SUSY based on simplicity and naturalness. Out of 60 or so pages, only one is devoted to the models favored by Arkani-Hamed and Dimopoulos, string-theory based models are not even mentioned.