3 ms·
Neutrino Dark Matter
- lamontcg 4y agoLink to John Baez's blog, from Peter Woit's blog which has some other interesting links today: https://www.math.columbia.edu/~woit/wordpress/?p=13232 https://www.math.columbia.edu/~woit/wordpress/?p=13232
- PaulHoule 4y agoI am not an expert (I am a condensed matter physics PhD who doesn't work in the field) but I believe the dark matter particle is a right-handed neutrino. My argument is that the neutrino obviously has a mystery left in it because we don't know what the mass term looks like. It is not "physics beyond the standard model" but "a missing piece of the standard model". This nice paper makes the case that the right handed neutrino could wrap up the remaining mysteries in particle physics https://arxiv.org/abs/1303.6912 https://arxiv.org/abs/1303.6912
- jfengel 4y agoI'm even less of an expert, but as I understand it, neutrinos are too light to be cold-dark-matter. They move too fast to be held in galaxies, because their mass is so low. TFA sounds like they think that right-handed neutrinos could be massive, but they'd have to be much heavier than the limits they mention in the article to account for CDM. Also, AIUI, CDM requires some kind of non-gravitational interaction to account for the observed abundance. If right-handed neutrinos are sterile, can they be produced in sufficient numbers to constitute dark matter?
- lamontcg 4y agoThe arxiv article covers that. If the neutrinos are majorana then they are their own antiparticle so they don't interact with Higgs field. And with the lightest left handed neutrino massless then through the "seesaw mechanism" you can wind up with an exceptionally heavy right handed majorana neutrino, and by cosmology the mass needs to be around 4.8×10^8 GeV.