Resolving neutrino mass hierarchy from supernova (anti)neutrino-nucleus reactions

TL;DR

This paper proposes a hybrid detection method combining multiple neutrino and antineutrino signals from supernovae to determine the neutrino mass hierarchy, utilizing different target materials and flux models.

Contribution

It introduces a novel hybrid approach that uses simultaneous measurements from various detectors and target materials to resolve the neutrino mass hierarchy from supernova neutrino signals.

Findings

Simultaneous measurements can distinguish normal and inverted hierarchy.

Heavy nuclei detectors are more effective for neutrino detection.

Light nuclei and free protons are suitable for antineutrino detection.

Abstract

We introduce a hybrid method to determine neutrino mass hierarchy by simultaneous measurements of detector responses induced by antineutrino and neutrino fluxes from accretion and cooling phase of type II supernova. The (anti)neutrino-nucleus cross sections for $^{12}$C, $^{16}$O, $^{56}$Fe and $^{208}$Pb are calculated in the framework of relativistic nuclear energy density functional and weak Hamiltonian, while the cross sections for inelastic scattering on free protons, $p(\bar{\nu}_{e},e^{+})n$, are obtained using heavy-baryon chiral perturbation theory. The simulations of (anti)neutrino fluxes emitted from a protoneutron star in a core-collapse supernova include collective and Mickheev-Smirnov-Wolfenstein effects inside star. The emission rates of elementary decay modes of daughter nuclei are calculated for normal and inverted neutrino mass hierarchy. It is shown that simultaneous use of (anti)neutrino detectors with different target material and time dependence of the signal allow to determine the neutrino mass hierarchy from the ratios of $\nu_e / $ $\bar{\nu}_e$ induced particle emissions. The hybrid method favors detectors with heavier target nuclei ($^{208}$Pb) for the neutrino sector, while for antineutrinos the use of free protons and light nuclei ($\text{H}_2\text{O}$ or $\text{-CH}_2\text{-}$) represent appropriate choice.