This Standard Model has served us pretty well so far, but there are some significant holes, the most glaring being the fact that it doesn’t account for gravity. So for decades physicists have been trying to find physics occurring beyond the Standard Model, using machines such as the LHC to help them find clues. And now they may finally have a huge lead.
An international team of physicists has found hints of leptons – a specific type of subatomic particle – behaving in strange ways not predicted by the Standard Model. They uncovered this while looking at the decay of particles called B mesons into lighter particles, including two types of leptons: the tau lepton and the muon.
According to a key Standard Model concept called ‘lepton universality’, all leptons are treated equally by all fundamental forces, which means that all leptons should decay at the same rate, once corrected for any difference in mass. But in the data, the team found a small but notable difference in the predicted rates of decay. This suggests that some type of as-yet undiscovered forces or particles could be interfering.
“The Standard Model says the world interacts with all leptons in the same way. There is a democracy there. But there is no guarantee that this will hold true if we discover new particles or new forces,” one of the lead researchers, Hassan Jawahery, from the University of Maryland in the US, said in a press release. “Lepton universality is truly enshrined in the Standard Model. If this universality is broken, we can say that we’ve found evidence for non-standard physics.” Source: The LHC finds evidence of particle activity beyond the Standard Model