$\rho$ exchange contribution to neutrinoless double beta decay

TL;DR

This paper investigates the role of $ ho$ meson exchange in neutrinoless double beta decay, revealing significant effects on nuclear matrix elements and emphasizing the importance of including these contributions in theoretical models.

Contribution

It introduces the calculation of $ ho$ meson exchange contributions to neutrinoless double beta decay within the vacuum dominance approximation, highlighting their impact on decay amplitudes.

Findings

$ ho$ exchange leads to near cancellations in same-chirality amplitudes.

Left-right amplitudes are nearly tripled by $ ho$ exchange.

Inclusion of $ ho$ exchange is essential in phenomenological studies.

Abstract

We consider $\rho$ meson contributions to neutrinoless double beta decay amplitude stemming from the hadronization of the short distance quark-electron currents. These contributions are evaluated within vacuum dominance approximation. The one and two $\rho$ exchange contributions affect the Fermi transition nuclear matrix element in a way that lead to near cancellations in the same chirality, left-left and right-right, short range amplitudes when these new contributions are combined with the conventional short range amplitudes, while the left-right amplitude almost triples. This then necessitates the inclusion of $\rho$ exchange amplitudes in any phenomenological study, like in left-right theories.