Exploring the Neutrino Mass Hierarchy Probability with Meteoritic Supernova Material, {\nu}-Process Nucleosynthesis, and {\theta}13 Mixing

TL;DR

This study investigates how meteoritic supernova material and neutrino-process nucleosynthesis can provide clues about the neutrino mass hierarchy, suggesting a slight preference for the inverted hierarchy based on current data.

Contribution

It introduces a Bayesian analysis linking meteoritic isotopic data with supernova models to infer the neutrino mass hierarchy, considering recent constraints on  mixing angle.

Findings

Hints at a marginal preference for inverted hierarchy

Large uncertainties limit definitive conclusions

Future analysis of more meteoritic grains could clarify hierarchy

Abstract

There is recent evidence that some SiC X grains from the Murchison meteorite may contain supernova-produced {\nu}-process 11B and or 7Li encapsulated in the grains. The synthesis of 11B and 7Li via neutrino-induced nucleon emission (the {\nu} -process) in supernovae is sensitive to the neutrino mass hierarchy for finite sin^2(2{\theta}13) > 0.001}. This sensitivity arises because, when there is 13 mixing, the average electron neutrino energy for charged-current neutrino reactions is larger for a normal mass hierarchy than for an inverted hierarchy. Recent constraints on {\theta}13 from the Daya Bay, Double Chooz, MINOS, RENO and T2K collaborations all suggest that indeed sin^2(2{\theta}13) > 0.001}. We examine the possible implications of these new results based upon a Bayesian analysis of the uncertainties in the measured meteoritic material and the associated supernova nucleosynthesis models. We show that although the uncertainties are large, they hint at a marginal preference for an inverted neutrino mass hierarchy. We discuss the possibility that an analysis of more X grains enriched in Li and B along with a better understanding of the relevant stellar nuclear and neutrino reactions could eventually reveal the neutrino mass hierarchy.