A 99.95% certainty
A review of three separate experiments has turned up "remarkably similar"
results, pointing to what researchers say is a strong possibility that
we've found hits of a phenomenon that goes beyond the standard model of
When taken together, data from experiments conducted in the US,
Switzerland, and Japan, have yielded a result with 99.95 percent
certainty that lepton universality - a fundamental assumption of the
standard model - does not hold up.
"These studies have resulted in observations that seem to challenge lepton universality," an international team of physicists reports.
"A confirmation of these results would point to new particles or
interactions, and could have profound implications for our understanding
of particle physics."
If you're unfamiliar with lepton universality,
it's actually a pretty simple concept - that the interactions of
certain elementary particles are the same, despite those particles
having different masses and lifetimes (decay rates).
The particles in question are called charged leptons, and they include electrons, muons, and the much heavier taus.
What the three experiments found is that, when considered in relation
to the decay rates of electrons and muons, tau decay rates are much
higher than they should be.
In other words, taus decay quicker than the standard model of
particle physics predicts, based on the principle of lepton
And that's strange, because the result from one experiment could
easily be a mistake, but all three experiments observed a
higher-than-expected tau decay rate, despite the fact that they were all
operating in different environments.
"The tau lepton is key, because the electron and the muon have been
well measured. Taus are much harder because they decay very quickly," says one of the team, Franco Sevilla from the University of California - Santa Barbara...
Full story: http://www.sciencealert.com/3-separate-experiments-have-found-signs-of-a-phenomenon-beyond-the-standard-model-of-physics