Déterminer la hiérarchie des masses des neutrinos grâce à la prochaine supernova galactique ✛ ✦

Résumé original

tel que rédigé par les auteurs, en anglais arXiv:2606.06580v1

The next Galactic core-collapse supernova (CCSN) will offer a unique opportunity to determine the neutrino mass ordering. We focus on two observables: the electron neutrino ($$ u_e$$) neutronization burst and the rise-time of the electron antineutrino ($$\bar{ u}_e$$) flux during the accretion phase. The neutronization burst, a sharp $$ u_e$$ peak within $$\sim 20$$-$$30$$ ms, provides a clean and robust signature of mass ordering through its appearance or disappearance. During the accretion phase, the faster rise of heavy lepton flavor neutrinos ($$ u_x$$) leads to a distinct faster rise-time behavior of the oscillated $$\bar{ u}_e$$ signal, resulting in mass ordering discrimination. Using realistic CCSN simulations for multiple progenitor masses, we compute event rates and perform a statistical analysis for a Galactic ($$10$$~kpc) CCSN event at DUNE, Hyper-Kamiokande (HK), and JUNO detectors. The neutronization burst remains largely independent of SN hydrodynamic simulation models, with DUNE and HK achieving $$\gtrsim 6\sigma$$ and $$\gtrsim 4\sigma$$ sensitivity for normal (NO) to inverted ordering (IO) discrimination, respectively. However, the rise-time observable is prone to progenitor degeneracies. To mitigate this cumulative and ratio-based observables constructed at characteristic timescales ($$20$$ ms & $$100$$ ms) are used. The resulting confidence levels from the rise-time analysis to discriminate IO/NO in HK and JUNO are $$\sim 5\sigma$$ and $$\sim 3\sigma$$, respectively. Our results highlight the complementarity of detectors and observables, and demonstrate that combining neutronization burst and accretion phase information will be crucial for a definitive determination of the neutrino mass ordering in the next Galactic supernova.