Researchers with the T2K experiment found that muon neutrinos morphed into
electron neutrinos more often than expected, while muon antineutrinos became electron antineutrinos less often.
Not exact matches
The three types of
neutrino —
electron, tau and muon — interact with the matter in slightly different ways, with the
more massive muon and tau varieties able to escape from deeper within the neutron star.
Using
more limited data, Hill sees background signals and possible
electron antineutrino events in roughly equal number, and concludes that there is no evidence for a
neutrino mass.
Here, too, the experiment detected a different mix of
neutrinos than expected — in this case, fewer
electron neutrinos and
more taus and muons.
The key for NOvA is that the greater the mass of the
electron neutrino flavor, the
more likely the beam of
neutrinos will interact with the hundreds of miles of matter they cross on the way to the detector.
Scientists know the mass of every other fundamental particle, such as the
electron, but the
neutrino — at least a million times as light as the
electron — is far
more elusive because of its transformative ways.
Randall is also open to the idea of
more particles, just as normal matter consists of a slew of subatomic entities, including quarks,
electrons and
neutrinos.
For
more than three decades, physicists have been looking for, well, next to nothingelementary particles of matter called
electron -
neutrinos that have no charge and practically no mass.
For example, an
electron neutrino —
more precisely, an
electron antineutrino — emerges when an atomic nucleus such as tritium undergoes a type of radioactive decay called «β decay» and turns into a slightly less massive helium - 3 nucleus while spitting out an
electron and an antineutrino.
That was the Liquid Scintillator
Neutrino Detector (LSND) at the Los Alamos National Laboratory in New Mexico, which in data acquired between 1993 and 1998 showed muon antineutrinos to be oscillating into
electron antineutrinos far
more readily than expected.
In fact, of the total matter in the universe, the overall mass of the exotic particles is five times the overall mass of the «ordinary matter» we are
more familiar with (matter made of protons, neutrons,
electrons,
neutrinos, etc.).