Summer's almost gone

The season of the year known as summer conferences is over now. What will follow is probably two quiet months when particle physicists make provisions for winter. The LHC has recently restarted at a higher-than-ever luminosity in a bid to double the 2011 data set. Interesting new results are therefore not expected before November when the current run will end. All in all, this is a perfect moment for a post of the sort d'où venons nous blabla. Here's a summary of the most important events and cultural phenomenons of the past summer.

• Higgs Chase
  It was like one of these action movies where a fugitive surrounded by hundreds of police with guns and helicopters manages to escape disguised as a hostage. The odds of discovering Higgs this summer were significant, but the bugger chose its parameters so as to maximize the difficulty of being found. Nevermind, next time. A plot from this talk of Bill Murray, which is just an extrapolation of the current search sensitivity to larger data sets, shows that we're very close now to ultimate answers. With 5 inverse femtobarns of data CMS alone should be able to get a 3-4 sigma exclusion even in the worst possible case of a 115 GeV Higgs. ATLAS looks worse on that plot because their pT threshold for detecting leptons is set higher than that of CMS. This fact does not matter too much for a moderately heavy Higgs, but for a light one it punishes them (it's then easier to miss the H → WW → 2l 2ν decay which would produce rather soft leptons). If this can be improved we'll get an even better reach after combination of ATLAS and CMS data, close to the CMSx2 line. So by the end of the year we should know much more than today: 5 sigma discovery probably no, 3 sigma hint or exclusion probably yes.
• Apocryphal Combinations
  That was definitely the hit of the summer, on par with James Blunt. Although experts warn about their quality, although CERN authorities threaten with corporal punishment to anyone caught watching one, bootleg combinations of ATLAS and CMS Higgs results are thriving on blogs and even in LHC experimenters' talks. Coming next are apocryphal data analyses and, who knows, maybe apocryphal colliders.
• Conference Revival
  During the past decade particle physics conferences have been a sad and boring display. With the LHC running at full speed things have changed a lot. At least in theory, a spectacular discovery may now occur anytime which creates big expectations and excitement around the major conferences. Of course, in the 21st century there is no logical reason to present results at conferences. Experimental results could be presented for example once they're ready, and the presentations more efficiently via internet. Nevertheless, one should not neglect the important convivial aspects of conferences which play a similar role to maypole festivities in pagan societies. Not to mention that the conference deadlines provides an efficient whip for PhD students to finish the analysis in time.
• SUSY Scorned
  They say you don't kick a man when he's down. Another approach, more popular where I come from, is that it is precisely the best moment as he has limited options to retaliate. I'm somewhat torn between these two approaches. On one hand, watching someone once noble being tarred-and-feathered is always delightful. On the other hand, I sympathize with the view that the backlash against SUSY that is currently unfolding in the mainstream media has no logical grounds. Before the LHC one had to believe in a hundred of new particles just behind the corner who conspire not to break any of the accidental/approximate symmetries of the Standard Model such as the baryon, flavor, or CP symmetry, and in addition their contributions to the electroweak scale accidentally cancel at the 1% level. Now one has to believe in a hundred of new particles just behind the corner who conspire not to break any of the accidental symmetries of the Standard Model, whose contributions to the electroweak scale accidentally cancel at the 1% level, and who do not produce spectacular signals in the early LHC data. In this sense, the summer 2011 LHC results only infinitesimally changed the situation of supersymmetry.
• Nihil Novi
  Unfortunately, it's not only SUSY that is missing; new physics in whatever form obstinately refuses to show up. Not even a rumor these days... Especially disappointing is that the LHC, unlike the Tevatron, does not see any non-standard effects in top physics. Before, I was estimating the chances of LHC discovering new physics at about 50%. Now it is closer to 33%. The moment we discover the Higgs looking roughly like the Standard Model one, these chances will drop face down...
• Sunset of Tevatron
  This summer we have watched the Tevatron falling helter-skelter into obsolete. In most of the analyses the sensitivity of the LHC is now far superior. There are some notable exceptions though, such as the top and W mass precision measurement, light Higgs decays to b-quarks, and the forward-backward asymmetry of the top quark production. For these and other reasons, even though Tevatron's life-support will be switched off at the end of this month, the ghost will haunt us a little longer.

To finish with important events of this summer, Resonaances now has a Twitter account. Well, these days every celebrity has one ;-) Disappointingly, you won't learn from it what I had for breakfast, or about my views on the political tensions in southern Uzbekistan. It is going to be a low-traffic twitter limited to announcing new posts on Resonaances, pointing to interesting papers, blog posts and articles elsewhere, and spreading lesser rumors and gossips.