Gauge vectors and double beta decay

TL;DR

This paper analyzes how vector bosons from various gauge groups can contribute to neutrinoless double beta decay, identifying realistic gauge candidates and setting mass and mixing constraints based on experimental non-observation.

Contribution

It systematically classifies vector contributions to $0 uetaeta$ decay up to dimension 11 and links them to gauge groups, deriving phenomenological bounds.

Findings

Few gauge vectors can realistically contribute to $0 uetaeta$ decay.

Derived lower limits on gauge boson masses from decay non-observation.

Set bounds on mixing angles for relevant gauge bosons.

Abstract

We discuss contributions to neutrinoless double beta ($0\nu\beta\beta$) decay involving vector bosons. The starting point is a list of all possible vector representations that may contribute to $0\nu\beta\beta$ decay via $d=9$ or $d=11$ operators at tree-level. We then identify gauge groups which contain these vectors in the adjoint representation. Even though the complete list of vector fields that can contribute to $0\nu\beta\beta$ up to $d=11$ is large (a total of 46 vectors), only a few of them can be gauge bosons of phenomenologically realistic groups. These latter cases are discussed in some more detail, and lower (upper) limits on gauge boson masses (mixing angles) are derived from the absence of $0\nu\beta\beta$ decay.