2
$\begingroup$

Since neutrinos are only subjected to weak interaction(ignore gravitation), thus the interaction of neutrinos are only governed by Z bosons, and photon is unlikely produced. If two neutrinos annihilate at an energy scale sufficient to produce a Z boson, then the Z boson can decay into various particles including photons. But what if the energy scale is insufficient for Z boson production? Does that mean the neutrinos will never annihilate?

$\endgroup$
  • $\begingroup$ Two low energy neutrinos don't have the energy to annihilate into a real Z. $\endgroup$ – CuriousOne Sep 23 '15 at 4:30
  • $\begingroup$ Perhaps $\nu\bar\nu \to W^+W^- \to \gamma\gamma$? It'd be super-suppressed. Note that according to the PDG, $Z\to\gamma\gamma$ decays are ruled out at the part-per-million level for lone $Z$s. $\endgroup$ – rob Sep 23 '15 at 4:45
2
$\begingroup$

Low energy neutrino and antineutrino can annihilate into three photons, but with an extremely low cross-section. So it's not "never", it's "hardly ever" (http://www.sciencedirect.com/science/article/pii/0029558266902331)

| cite | improve this answer | |
$\endgroup$
  • $\begingroup$ Why? The neutrinos don't experience electromagnetism. $\endgroup$ – Ballistics Sep 23 '15 at 6:20
  • $\begingroup$ So it can be infered that the prospect of double beta decay experiment is very dark. $\endgroup$ – Ballistics Sep 23 '15 at 6:23
0
$\begingroup$

Maybe the neutrino and anti-neutrino could annihilate virtually, creating a virtual Z boson. Then the virtual Z boson could decay into particles depending on the energy of the neutrino and anti-neutrino.

| cite | improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

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