Effect of Spin-Dependent Short-Range Correlations on Nuclear Matrix Elements for Neutrinoless Double Beta Decay of $^{48}$Ca

TL;DR

This study investigates how spin-dependent short-range correlations influence nuclear matrix elements in neutrinoless double beta decay of calcium-48, revealing a 10-20% difference compared to traditional methods, which impacts neutrino physics research.

Contribution

It introduces a detailed analysis of spin-dependent SRC effects on NMEs for $^{48}$Ca decay using an extensive shell model, highlighting differences from conventional approaches.

Findings

Spin-dependent SRC cause 10-20% variation in NMEs.

NMEs depend on intermediate states, spin-parity, neutrino momentum, and closure energy.

Distinct effects observed compared to Jastrow-type SRC methods.

Abstract

The neutrinoless double beta decay is a pivotal weak nuclear process that holds the potential to unveil the Majorana nature of neutrinos and predict their absolute masses. In this study, we delve into examining the impact of spin-dependent short-range correlations (SRC) on the nuclear matrix elements (NMEs) for the light neutrino-exchange mechanism in neutrinoless double beta ($0\nu\beta\beta$) decay of $^{48}$Ca, employing an extensive interacting nuclear shell model. All computations are performed employing the effective shell model Hamiltonian GXPF1A, encompassing the entire $fp$ model space through the closure approximation. Our investigation examines the NMEs' dependencies on factors such as the number of intermediate states, coupled spin-parity attributes of neutrons and protons, neutrino momentum, inter-nucleon separation, and closure energy. This scrutiny is performed with respect to both the conventional Jastrow-type approach of SRC, employing various parameterizations, and the spin-dependent SRC paradigm. Our findings illuminate a discernible distinction in NMEs induced by spin-dependent SRC, differing by approximately 10-20\% from those computed through the conventional Jastrow-type SRC, incorporating distinct parameterizations.