1
$\begingroup$

I was thinking about how in materials near absolute zero the debroglie wavelength of the electrons in the atoms is very large, and it occurred to me from physics that one reason why neutrinos are not easily absorbed by matter is because the neutrino wave function has to overlap with the wave function of atomic nuclei, I believe. If that's the case, then could nuclei at temperatures near absolute zero absorb more neutrinos because of the nuclei having spread out wave functions? On the other hand, I'm not sure if it factors into electroweak physics like that, but that's why I'm asking. For the sake of this question, I'm only caring about electron neutrinos.

$\endgroup$

1 Answer 1

1
$\begingroup$

The reaction of a neutrino with matter is typically:

$$ \nu + \text{n} \rightarrow \text{p} + \ell $$

where $\ell$ is an electron, muon or tau depending on the flavour of the incoming neutrino.

So the neutrino is interacting with a neutron (more precisely with one of the quarks in the neutron) and the neutrino will be travelling at very nearly the speed of light relative to the neutron. Changing the temperature will make the nucleus, and therefore the neutrons in it, vibrate but the thermal velocities involved are utterly negligable when compared to the speed of light. So temperature will have no effect on the cross section per nucleus.

However there will be an effect due to density changes. Most materials get denser with decreasing temperature so they have more neutrons per cubic metre for the neutrino to hit.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.