$L_\mu-L_\tau$ gauge bosons in beam dumps and supernovae

TL;DR

This paper investigates the phenomenology of a sub-GeV $L_-L_ au$ gauge boson, revising sensitivity estimates for experiments and re-evaluating supernova cooling constraints with new analysis methods.

Contribution

It provides a corrected sensitivity analysis for beam dump experiments and introduces new supernova-based probes for the $L_-L_ au$ gauge boson.

Findings

Revised sensitivity projections for the SHiP experiment.

Updated supernova cooling bounds from SN1987A.

Identification of additional supernova-based constraints.

Abstract

We study the phenomenology of a sub-GeV $L_\mu-L_\tau$ gauge boson. We find discrepancies with existing literature in sensitivity projections for the upcoming SHiP experiment and in the treatment of supernovae cooling constraints. We present a quantitative analysis of different production modes in beam dumps and compare our results to previous work. In the context of supernovae, we re-evaluate the standard supernova cooling bounds from SN1987A and analyze additional supernova-based probes: diffusive cooling, constraints from the existence of low-energy supernovae, and the absence of a high-energy neutrino signal from SN1987A.