It’s a pincer attack on new physics. The sister project to the CMS and ATLAS collaborations at the LHC CERN, LHCb has just released new data which spells a death knell for supersymmetry. Okay, that might be a hasty statement, but if the results are really what they are, it’s very unlikely that any ‘reasonable’ model of supersymmetry will be able to survive.
Why the LHCb?
The LHC collaborations CMS and ATLAS have been the mainstay of the group and recently enjoyed huge success in the discovery of the Higgs Boson. Less publicized and more specialist in their study is the LHCb detector and its collaboration. This detector is specialized for measuring certain exotic particles – those made up of at least one bottom quark. Since the bottom quark is very heavy, and heavy particles tend to decay very fast, all particles with the bottom quark are very short-lived making their study very difficult. And this is where LHCb specializes in.
Now the result
LHCb announced a new observation today and it knocks the wind out of supersymmetry. Let me tell you the observation and then tell you what it implies. They observed the decay of a certain particle called the Bs meson (B=Bottom and s=strange). The decay rate of this particle hadn’t been measured before with much accuracy, but today the LHCb collaboration announced that they have measured it and found that it decays into two muons about 3-4 times per billion decays. The ‘bingo’ moment for non-supersymmetric particle physics is that this is exactly what the Standard Model predicts. Right on the dot!
There is another storm brewing. It turns out that the Higgs Boson discovered earlier isn’t behaving as well as it should! Notably, it is not decaying into two tau leptons as often as it should. In fact, it seems that it is not decaying into tau leptons at all. There is a problem!
And the bad news
These two problems are pulling in opposite direction squeezing the super-symmetric space that lies between them. If the Bs decaying into two muons is exactly like what the Standard Model says, then supersymmetry, which predicts a higher decay rate, must obviously be constrained. And very heavily so!
So there it is! Supersymmetry is teetering on the edge of oblivion. But it may yet survive…
The public conference result: http://lhcb-public.web.cern.ch/lhcb-public/