The experiment LHCb (Large Hadron Collider beauty) located at the European Laboratory for Particle Physics (CERN) has observed new results that, if confirmed, would suggest indications of a violation of the standard model of particle physics. These results were recently announced at the Moriond conference and at a seminar held at CERN.
LHCb is one of the four major experiments at CERN’s Large Hadron Collider, located underground on the Franco-Swiss border near Geneva. It is designed to compare two types of disintegration of quarks beauty, a fundamental type of particle. In the first disintegration the electron and in the second the muon, another elementary particle similar to the electron but about 200 times heavier.
The latest results from CERN’s LHCb experiment show evidence of the deviation from lepton universality between the electron and muon, which if confirmed would be an indication of a violation of the standard model of particle physics.
The electron and the muon, along with a third particle called tau, are types of leptons and the difference between them is called ‘flavors‘. The standard model of particle physics predicts that decays involving different flavors of leptons, such as the one in the LHCb study, should occur with the same probability, a characteristic known as lepton universality that is usually measured by the ratio of the probabilities of disintegration. In this model, the relationship should be very close to one.
The latest results show indications of the deviation of the lepton universality between the electron and muon: the statistical significance of the result is of 3.1 standard deviations, which implies a probability of about 0.1% that the data are compatible with the predictions of the standard model.
“If a violation of the universality of the taste of leptons were confirmed, a new physical process would be required, such as the existence of new particles or fundamental interactions,” says LHCb spokesman Professor Chris parkes, from the University of Manchester and CERN, which notes: “Further studies on related processes are under way using existing data from the LHCb. We would be delighted to see if they reinforce the intriguing evidence from current results.
All LHCb data
This deviation is consistent with a pattern of anomalies measured in similar processes by LHCb and other experiments around the world during the last decade. The new results determine the relationship between decay probabilities with greater precision than previous measurements and use for the first time all the data collected by the LHCb detector so far.
“Although cautious, these results are very exciting because they are persistent in the behavior of the previous ones, now with more data and more systematic studies that rule out possible experimental effects. The new results of similar processes that hope to see the light in the coming months will be key, “the researchers said. Arantza Oyanguren Campos Y Fernando Martinez Vidal, two of the IFIC researchers participating in LHCb.
Looking ahead, the LHCb experiment is well placed to clarify the possible existence of new physical effects hinted at in the decays analyzed in this study. The LHCb experiment is expected to begin collecting new data next year after a detector update.
Deviations in terms of standard deviation between the experimental measurements (in blue) and the theoretical predictions (yellow) of the new result (RK) and similar processes by LHCb and other experiments obtained during the last decade. / IFIC
Fountain: CERN / IFIC
Rights: Creative Commons.