Scientists challenge the Standard Model of Particle Physics

The results of three different experiments have turned out to be quite alike, an indication that the Standard Model of particle physics might not exactly be what it is.

The Standard Model of particle physics depicts that the interactions of the charged leptons which include electrons, muons and taus are the same regardless of their dissimilar masses and lifetimes (decay rates). This is also known as the lepton universality, and recent studies have generated certain observations that might challenge this theory.

Information from the experiments conducted by team on international physicists in US, Switzerland and Japan, predicted a 99.95% conviction that lepton universality does not hold up.

The study appearing in the journal Nature stated the international physicists’ team reporting, “These studies have resulted in observations that seem to challenge lepton universality. A confirmation of these results would point to new particles or interactions, and could have profound implications for our understanding of particle physics.”

The three experiments predicted that tau’s lifetime is much higher than it should be as compared to the decay rates of electrons and muons. In short, taus decay much quicker than the Standard Model predicts.

What’s astonishing is that the results from all the three experiments indicated a higher-than-expected tau decay rate, keeping in view that all the three experiments were conducted in different parts of the world with different environments, informs Science Alert.

“The tau lepton is key, because the electron and the muon have been well measured. Taus are much harder because they decay very quickly,” expresses one of the team, Franco Sevilla from the University of California. “Now that physicists are able to better study taus, we're seeing that perhaps lepton universality is not satisfied as the standard model claims.”

When evaluated together, the results challenged the basic ideology of lepton universality at a level of 4 standard deviations which is a 99.95% certainty as per the US team. However, the scientists still need 5 standard deviations in order to prove the theory completely wrong.

According to Phys.org, Franco Sevilla explained, “We're not sure what confirmation of these results will mean in the long term. First, we need to make sure that they're true, and then we'll need ancillary experiments to determine the meaning.”