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.
14 years ago
Shall we branch out into chemistry now?
ReplyDeleteWell, clearly combination's of neutrons and protons can be Bosons yes?
ReplyDeleteThe PeSla
Lol, ThePeSla. Physicists have many names for particle groupings, but I think I prefer to stick to the word Atom for nuclei composed of protons and neutrons.
ReplyDelete"neutrons in nuclei are mirror neutrons, and free neutrons are ordinary neutrons."
ReplyDeleteNeutrons in nuclei would then belong to antimatter?
In a sense, yes, because they annihilate with so called antineutrons, which are essentially the same thing, having equal mass and charge.
ReplyDeleteInteresting. There should be superpositions of the real and mirror particles; these would not have sharp masses. I'm guessing that these are the ones that would be used inside nucleons. That way, you don't have to create anything when you spit out a real neutron.
ReplyDeleteThe whole thing about what is "matter" and what is "antimatter" is personal preference; Experimentally, an antiparticle is something that annihilates nicely with a particle.
(This may not make a lot of sense, I'm still in shock to hear that you'll have to leave Wellington.)
http://en.wikipedia.org/wiki/Deuterium
ReplyDeleteThe overall magnetism of an atom is determined by how many electrons spin which way on a sub-shell and decades ago there was no explanation for this. Then came a model of the nucleus where the Nucleons were treated in sub-shells as if pairs of them. These are most likely very obsolete ideas, but I do see the nucleons a sort of four way deal- I am not sure we can make analogies to the neutrinos but then that is what these measurements are all about. This is the sort of restriction we imagine that may just go a little deeper than ideas of superposition. This side of the mirror anyway.
The PeSla