This might be a big deal if it is verified. Some physicists have long thought that the solution to the lower than expected flux of solar neutrinos observed here on Earth was that the neutrinos were changing “flavor” in flight. There were three expected flavors, the electron, the muon and the tau – each corresponding to the appropriate lepton, and representing a family of elementary particles.
(Parenthetically, the idea that neutrinos can change flavor in flight (which is now considered experimentally verified) indicates that neutrinos have a non-zero mass. Which means they’re good candidates for being a form of hot dark matter.)
“‘We’ve only had evidence for three kinds of neutrinos so far, but a recent test at Fermilab involving an antineutrino beam has reinforced a Michigan researcher’s earlier experiment suggesting a fourth flavor. What’s really odd about this is that a prior neutrino test (carried out as part of project MiniBooNE) did not result in indications of such strange oscillations. According to the researcher, ‘The simplest explanation involves adding new neutrino-like particles, or sterile neutrinos, which do not have the normal weak interactions.’ But this could also be an unknown or misunderstood effect. A Los Alamos National Laboratory scientist added that an explanation of this strange anomaly could result in understanding ‘matter asymmetry of the universe, or why the universe is primarily composed of matter, rather than antimatter.’ The results are published in the Physical Review Letters.'”
More here plus live links to all the referenced stories.
So if there’s a fourth flavor observed, I suppose it could mean there’s an elementary particle family that’s more massive than the top/bottom/tau/tau neutrino family – or it could mean the whole mass spectrum classification is an illusion (like Hubble’s galactic tuning fork diagram has turned out to be.)