LHCb Detects Decays of B-Mesons Which Hints At New Physics

The most promising signatures of something beyond what we know have been coming consistently from an experiment in LHC, CERN that has received the least public attention. While the CMS and ATLAS detectors (and collaborations) at the LHC are running their proton beams day and night in search of several things, primary among them being the Higgs Boson, the other big experiment, the LHCb, has been quietly chugging along with its own set of measurements.

Part of the LHCb detector

The latest from the LHCb detector, housed in the same compound as the CMS and ATLAS, is a result that just might signal physics from Beyond the Standard Model (BSM), fashionably titled New Physics. BSM has been a devoutly investigated area of interest for both CMS and ATLAS, but the LHCb focusses on very specific types of particles and observes their modes of decay.

‘Exotic’ Physics

The types of particles LHCb is interested in contains a very exotic type of quark – the bottom quark. Protons and neutrons don’t contain that quark; they are entirely made up of ‘up’ and ‘down’ quarks. The Standard Model accurately predicts the decay rates and lifetimes of particles and, so far, experiments and theory have always matched. The recent LHCb result, adding to a few other ‘anomalous’ results of the past, show deviation from the theoretical values. Of course, no one is jumping into the BSM bandwagon just yet, but there is clearly excitement.

The Result

The LHCb collaboration found that a specific decay – a B-meson (i.e. a particle containing the bottom quark) becoming a kaon (another short-lived ‘exotic’ particle) along with a muon-antimuon pair. Muons are like heavy electrons. The LHCb collaboration observed that there is a difference in the decay rates between a neutral B-meson going to a neutral Kaon-muon-anti-muon and a positive B-meson going to a positive Kaon-muon-antimuon. This difference – called ‘isospin asymmetry’ – is not predicted by the Standard Model and this is what is interesting.

More data is required to confirm whether this is really a BSM signal.

The CERN bulletin:
The LHCb detector website:


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Debjyoti Bardhan

Is a science geek, currently pursuing some sort of a degree (called a PhD) in Physics at TIFR, Mumbai. An enthusiastic but useless amateur photographer, his most favourite activity is simply lazing around. He is interested in all things interesting and scientific.