Neutrinoless double beta decay in a supersymmetric left-right model

TL;DR

This paper investigates neutrinoless double beta decay within a supersymmetric left-right model (SUSYLRM) using an effective field theory framework that separates long-range and short-range contributions, with the parity-breaking scale $M_R$ serving as the new-physics scale. It systematically constructs the $0\nu\beta\beta$ amplitude from SUSYLRM-induced operators, expressing results through dimensionless $\eta$ parameters and nuclear matrix elements, and classifies contributions into six categories across long- and short-range mechanisms. Numerical analysis uses benchmark points and scans $m_{\chi^0_1}$, $m_{\tilde{\nu}_1}$ over a wide range and considers $M_R = 1$–4 TeV, finding that larger $M_R$ yields longer half-lives and that lightest SUSY particles can enhance observable signals; for $M_R = 4$ TeV the predicted half-life approaches $3\times 10^{27}$ years in Ge-76, within near-future experimental reach. The study highlights the potential interplay between $0\nu\beta\beta$ decay and dark matter phenomenology via the lightest neutralino and sneutrino, and discusses current collider and $0\nu\beta\beta$ constraints that shape the viable SUSYLRM parameter space. Overall, the work demonstrates how low-energy $0\nu\beta\beta$ measurements can probe the parity-breaking scale in SUSYLRM and inform dark matter considerations.

Abstract

Neutrinoless double beta ($0νββ$) decay, an important low-energy process, serves not only as a potential test of the Majorana nature of neutrinos, but also as a sensitive probe for new physics beyond the Standard Model. In this study, the supersymmetric left-right model is explored to investigate its impact on $0νββ$ decay. Although the process takes place at low energies as compared to the electroweak scale, it carries the potential to provide indirect hints about the parity-breaking scale $\text{M}_R$. In this work, we formulate the decay amplitude using an effective field theory approach by separating long- and short-range contributions, each expressed in terms of dimensionless particle physics parameters and nuclear matrix elements. The analysis shows that the $\text{M}_R$ must lie above $1$ TeV, and future experiments may push it beyond $4 - 5$ TeV region. Another important outcome of this work is the role played by the tentative dark matter candidates, the lightest neutralino and sneutrino, which contribute significantly to the half-life of $0νββ$ decay. This suggests that if any supersymmetric particle is detected in future experiments, dark matter candidates will gain a permanent position in these extensions of the Standard Model.

Figures (8)

• Figure 1: The possible classes of effective vertices for neutrinoless double beta decay connecting the SM to BSM theories. Figure (\ref{['fig:a']}) refers to the complete effective vertex diagram, which can be decomposed into the rest of the diagrams. On the right side, all three diagrams in the upper line are long-range in nature, whereas the rest of the three diagrams below are short-range interactions.
• Figure 2: The simplest possible diagram for $0\nu\beta\beta$ decay.
• Figure 3: The two diagrams represent the possible SUSYLRM diagrams for the effective diagram shown in Fig.(\ref{['fig:c']}).
• Figure 4: The SUSYLRM diagrams of the effective diagram Fig.(\ref{['fig:d']}). The triangle loops consist the SUSYLRM fields.
• Figure 5: The SUSYLRM counterparts of the effective vertex shown in Fig.(\ref{['fig:e']}).