The European organisation for nuclear research (CERN) on Tuesday came out with a news that has more than raised an eyebrow among particle physicists. The LHCb experiment in CERN has shown a feeble but persistent sign of physics that contradicts a basic assumption of the Standard Model, indicating that this theory which has ruled the roost may not be complete in itself.
The cautiously worded news update on the CERN website mentioned that this result, which has a statistical significance of 2.2-2.5 sigma “in two bins,”is not conclusive in itself and needs support from further investigations. However experts feel that this is a very big discovery.
Dr. Rahul Sinha, a faculty member at The Institute of Mathematical Sciences, Chennai, and who has done pioneering work in this sector, says, “It is a giant step towards discovering new physics. The effect is big and people around the world will work to explain this.”
So what is it that LHCb has found?
At the subatomic level, there are two types of processes that have been compared by the physicists at LHCb. One is the decay of what is called a B meson into an excited K meson and a pair of muons (muon-plus and muon-minus). The other is where the B meson decays into K meson giving an electron-positron pair.
According to the standard model, since the muons and electrons are identical except for their masses, the rates of these two reactions should be the same. However, the carefully done experiment finds the rates are quite different. The researchers have taken care to factor out all the experimental error possibilities.
Dr. Amol Dighe of Tata Institute of Fundamental Research, a particle physicist working on the physcs of LHCb, advocates caution. “
They have announced a confidence level of around 97%. As such it constitutes an ‘indication’ and not a ‘discovery’. I will wait for this to go higher,” he says. Dr Dighe adds that in the next run, the LHCb will get five times more data and since they have set up the experiment carefully, they will likely get a better result.