Manifestations of non-zero Majorana CP violating phases in oscillations of supernova neutrinos

TL;DR

This paper explores how non-zero CP violating phases, especially Majorana phases, influence neutrino-antineutrino oscillations in supernovae, potentially revealing the neutrino's fundamental nature through future observations.

Contribution

It demonstrates that CP phases can induce new resonances in supernova neutrino oscillations, affecting observable neutrino flux ratios and offering a method to distinguish neutrino types.

Findings

CP phases induce new oscillation resonances in supernova environments.

Neutrino-antineutrino oscillations can alter the ar_e/ ratio from supernovae.

Effects are more prominent with normal neutrino mass ordering.

Abstract

We investigate effects of non-zero Dirac and Majorana CP violating phases on neutrino-antineutrino oscillations in a magnetic field of astrophysical environments. It is shown that in the presence of strong magnetic fields and dense matter, non-zero CP phases can induce new resonances in the oscillations channels $\nu_e \leftrightarrow \bar{\nu}_e$, $\nu_e \leftrightarrow \bar{\nu}_\mu$ and $\nu_e \leftrightarrow \bar{\nu}_{\tau}$. We also consider all other possible oscillation channels with $\nu_\mu$ and $\nu_\tau$ in the initial state. The resonances can potentially lead to significant phenomena in neutrino oscillations accessible for observation in experiments. In particular, we show that neutrino-antineutrino oscillations combined with Majorana-type CP violation can affect the $\bar{\nu}_e$/$\nu_e$ ratio for neutrinos coming from the supernovae explosion. This effect is more prominent for the normal neutrino mass ordering. The detection of supernovae neutrino fluxes in the future experiments, such as JUNO, DUNE and Hyper-Kamiokande, can give an insight into the nature of CP violation and, consequently, provides a tool for distinguishing the Dirac or Majorana nature of neutrinos.