Nuclear matrix elements of neutrinoless double beta decay with improved short-range correlations

TL;DR

This paper calculates nuclear matrix elements for neutrinoless double beta decay in several isotopes using an improved method for short-range correlations, impacting neutrino mass sensitivity assessments.

Contribution

It introduces a comparison of traditional Jastrow and advanced UCOM methods for short-range correlations in matrix element calculations, showing significant differences.

Findings

UCOM yields larger matrix elements than Jastrow.

Results influence the sensitivity analysis of double beta decay experiments.

Provides updated nuclear matrix elements for key isotopes.

Abstract

Nuclear matrix elements of the neutrinoless double beta decays of 96Zr, 100Mo, 116Cd, 128Te, 130Te and 136Xe are calculated for the light-neutrino exchange mechanism by using the proton-neutron quasiparticle random-phase approximation (pnQRPA) with a realistic nucleon-nucleon force. The g_pp parameter of the pnQRPA is fixed by the data on the two-neutrino double beta decays and single beta decays. The finite size of a nucleon, the higher-order terms of nucleonic weak currents, and the nucleon-nucleon short-range correlations (s.r.c) are taken into account. The s.r.c. are computed by the traditional Jastrow method and by the more advanced unitary correlation operator method (UCOM). Comparison of the results obtained by the two methods is carried out. The UCOM computed matrix elements turn out to be considerably larger than the Jastrow computed ones. This result is important for the assessment of the neutrino-mass sensitivity of the present and future double beta experiments.