Possible CP-Violation effects in core-collapse Supernovae

TL;DR

This paper investigates CP-violation effects in neutrino fluxes from core-collapse supernovae, confirming no effects for electron neutrinos at tree level but potential effects for muon and tau neutrinos, especially if their fluxes differ at the neutrinosphere due to new physics.

Contribution

It demonstrates that CP-violation effects are absent for electron neutrinos at tree level but can appear in muon and tau neutrinos, highlighting the role of physics beyond the Standard Model.

Findings

No CP-violation effects for electron neutrinos at tree level.

Potential CP-violation effects for muon and tau neutrinos.

Differences in muon and tau neutrino fluxes could indicate new physics.

Abstract

We study CP-violation effects when neutrinos are present in dense matter, such as outside the proto-neutron star formed in a core-collapse supernova. Using general arguments based on the Standard Model, we confirm that there are no CP-violating effects at the tree level on the electron neutrino and anti-neutrino fluxes in a core-collapse supernova. On the other hand significant effects can be obtained for muon and tau neutrinos even at the tree level. We show that CP violating effects can be present in the supernova electron (anti)neutrino fluxes as well, if muon and tau neutrinos have different fluxes at the neutrinosphere. Such differences could arise due to physics beyond the Standard Model, such as the presence of flavor-changing interactions.