Wikipedia:Reference desk/Archives/Science/2019 April 14

= April 14 =

Neutrinos interacting
If two or more neutrinos get close enough, will they interact by the weak force or any other manner? What happens?Rich (talk) 19:52, 14 April 2019 (UTC)
 * The chance of interaction is very low. But if an antineutrino and neutrino interact perhaps they will form two photons, or an electron – positron pair if they are higher energy. Graeme Bartlett (talk) 21:43, 14 April 2019 (UTC)
 * says no. (Don't feel bad; it's easy to miss that sentence.) Since they do have mass, in principle they will be gravitationally attracted to each other, but gravity is so weak and the neutrino mass is so incredibly tiny that this will be effectively undetectable. --47.146.63.87 (talk) 21:47, 14 April 2019 (UTC)
 * I have edited your link, note that is just a "suggestion". Also neutrinos with energies over 91GeV may scatter off each other using the neutral current. (I don't know if the CMB measurements have ruled this out). Graeme Bartlett (talk) 22:33, 14 April 2019 (UTC)
 * Yeah, and then I realized that's the wrong thing: it's about a single particle interacting with itself. I thought I was all clever searching the article for text. --47.146.63.87 (talk) 22:35, 14 April 2019 (UTC)
 * Also, this question from the Ref Desk archives may be of interest. --47.146.63.87 (talk) 22:31, 14 April 2019 (UTC)
 * This question was also useful. Essentially you are asking if there is a Yukawa potential (from a Yukawa interaction) affecting pairs of neutrinos.  This is an interesting search term ... seems like I end up going a different way every time though ... there are a lot of very clever physicists with ideas out there.  This time I ended up at  talking about how sterile neutrinos (only?) might interact with dark matter.  It can be perplexing.  But it is interesting, in that I think it is by considering the weak interactions of light particles that we might understand what the universe will do for interesting chemistry, physics, and people in the endless trillions of years after its "death" (in terms of our own high energy, short time scale physics) is over. Wnt (talk) 07:33, 15 April 2019 (UTC)