Axial-vector weak coupling at medium momentum for astro neutrinos and double beta decays

TL;DR

This paper investigates neutrino nuclear responses at medium momentum transfers relevant for astrophysical neutrinos and double beta decays, revealing a significant reduction in nuclear matrix elements due to axial vector coupling quenching.

Contribution

It provides experimental insights into the reduction of nuclear matrix elements at medium momentum transfer, highlighting the quenching of axial vector coupling in Te isotopes.

Findings

Nuclear matrix elements are reduced by a factor of about 0.35 compared to pnQRPA.

The reduction is attributed to quenching of the axial vector coupling g_A.

Results are relevant for modeling astrophysical neutrino interactions and double beta decay processes.

Abstract

Neutrino nuclear responses associated with medium momentum transfer of q=20-80 MeV for astro neutrinos and double beta decays were studied by using charge exchange reactions on Te128 and Te130. Gamow-Teller and spin dipole nuclear matrix elements are found to be reduced with respect to the pnQRPA matrix elements by the coefficient of around 0.35. The reduction is discussed in terms of the quenching of axial vector coupling (g_A).