If the MINOS results force us to rename the antineutrino in an attempt to respect CPT invariance, what about the other neutral particles whose apparent antiparticles have distinct masses? Recall that the neutron mass is around $1$ GeV, whereas the mass difference between neutrons and antineutrons is around $0.1$ MeV.
Now the free antineutrino is really a mirror neutrino, so one suspects that the free antineutron is secretly a mirror neutron. But this particle annihilates with neutrons in nuclei. So can the neutrons in nuclei secretly be mirror neutrons? It is beginning to look like this tower of cards should come crashing down, but consider this: neutrons in nuclei are mirror neutrons, and free neutrons are ordinary neutrons. So far we have been talking only about nomenclature, fully respecting all experimental facts.
With this scheme, neutrons and mirror neutrons have distinct masses, just like the neutrinos and antineutrinos. The free mirror neutrons annihilate with mirror neutrons in nuclei, which are $0.1$ MeV lighter than free neutrons. Now I was wondering about various vague energy threshold definitions for a fast neutron, when I discovered that deuteron formation occurs at a temperature of $kT = 0.1$ MeV. Deuteron formation is the process of the proton absorbing a free neutron.
6 years ago