RE: Antimatter, the mirror world (Particle Physics Series – Episode 4A)
Great post! For this time, I have only one remark (about neutrinos) and one more historical comment (Klein and Gordon) which may be useful to include in the text.
It is Paul Dirac that was able to reformulate Schrodinger’s equation within that frame
You are missing the Klein-Gordon equation, from 1926. Dirac equation came 2 years later. One of the problems with the Klein Gordon equation was that there were solutions with a negative energy, i.e. the antiparticles (a problem at that time). Dirac tried to get rid of them, but failed ;)
At the end of the day, those solutions were really there and antimatter was born. Okay, in fact, the right interpretation appeared later, in the 1940s.
The principle is the same for leptons. The electron has an electric charge Q = - 1 and a lepton number (L) of +1. Its antimatter counterpart, the positron (or anti-electron) has a charge and baryon number of same magnitude but of opposite sign: Q = + 1 and L = - 1.
Actually, lepton number does not have to be conserved, and neutrinos could be their own antiparticle (they are, in most models trying to explain neutrino masses). For instance, in the Standard Model, the neutrino mass term arises from the so-called 'Weinberg operator' that violates lepton number conservation by two units.
Thank you very much for the historical comment. I didn't know that. It is amazing how history "forgets" some of its contributors. there is a quite a probability for example that in a century or so, everyone will know about Higgs, yet many will have forgotten Englert and Brout...
Yes, if neutrinos are found to be majorama particles (if neutrinoless double Beta decays are finally experimentally confirmed), the Lepton number would be violated... I wonder how I should take it if this occurs ;-) It will just make particle physics more complicate to me lol!
Klein and Gordon are not really forgotten. Klein Gordon equation is in general taught before Dirac equation (it describes after all the dynamics of the Higgs boson) :)
For this reason, strictly speaking we must discuss the Higgs boson but the Brout-Englert-Higgs mechanism. Many of us are trying to stick to that in order to have justice for everyone.
For the specialist maybe, but I believe the profane knows the name of Dirac, yet Klein and Gordon might not be so recognized (for example, I didn't know them, I thought Dirac had done all the work).
Yet, I agree with you, recognition should be fairly spread out. I will attempt to mention more often the names of Englert and Brout when the Higgs Boson invites itself in my posts...
I will not change the name of my cat though. Her name is Higgsy ;-)
You thus want a clean Higgs :D
She also is very sociable, and interacts a lot with any human visiting me. Then, it requires a stronger effort from their part to leave. it's like if my cat was giving them extra mass...
Hey, maybe she's the extra Higgs Boson they are looking for at CERN, hiding in my sink, so not to be found
:-)
Higgs cascades! (the topic of one of my latest article, where heavy Higgses can be produced and then decays into lighter Higgses that themselves decay into the Standard Model Higgs) ^^