Back now from vacation, and found that there have been quite a few interesting talks at the KITP in Santa Barbara this week which are now available on-line:
Since the EPS-HEP conference last month, the “First Year of the LHC” program has some interesting results to discuss. Yesterday Matt Reece gave a talk on Assessing SUSY after 1 fb -1, on the hot topic of how worried SUSY proponents should be that no sign of SUSY has been found at the LHC so far. He takes the point of view that the failure of direct collider searches to see anything is much less of a problem than the pre-LHC failure of SUSY to show up indirectly in flavor physics or in cosmology. While it’s true that SUSY was in trouble pre-LHC, there’s psychologically a big difference between indirect effects not showing up, and directly looking for something and finding it’s just not there. The discussion with the audience is quite interesting, with some audience members a lot more worried about SUSY. One of them reminded people that SUSY is supposed to solve naturality problems, so relatively light squarks were expected, but now “those models are being screwed.” Someone else (Lisa Randall, I think) reacted to Reece’s mentioning R-parity violating models as one way to evade the LHC limits with “Is there any good reason to think about R-parity violation?” All in all, the discussion gives a good indication of what prominent theorists are thinking now that the initial results from the LHC are in.
About a year ago on this blog, I had the following exchange with a well-informed phenomenologist on this blog:
If there’s no sign of supersymmetry in this year’s LHC data, how discouraging will this be for those who expect to see supersymmetry at this energy scale?
In 2010 data? Not discouraging at all. In 2011 data? Fairly discouraging. In 2014 data? Enormously depressing.
The LHC has now gathered as much data as expected for all of 2011, so I think that with the negative results, “fairly discouraged” is where SUSY proponents would have expected to be and are now. “Enormously depressed” is on the agenda for late 2014, early 2015, after the LHC reaches design energy.
On the mathematical end of things, Ed Frenkel gave a very nice expository “Blackboard Lunch” talk on What do Fermat’s Last Theorem and Electro-magnetic Duality Have in Common?, explaining to physicists a bit about the Langlands program and the connection between geometric Langlands and QFT pioneered by Witten and developed by him and others over the past few years. For something more technical with newer ideas about the relationships between TQFT, gauge theory and representation, see David Ben-Zvi’s talk on Geometric Character Theory.