Constraints on $L_\mu-L_\tau$ Gauge Interactions from Rare Kaon Decay

TL;DR

This paper investigates how rare charged kaon decays can constrain the $L_{}-L_{ au}$ gauge symmetry model, which addresses the muon g-2 discrepancy, by proposing more sensitive experimental searches.

Contribution

It demonstrates that future kaon decay experiments with increased data and improved photon rejection can significantly test the $L_{}-L_{ au}$ gauge model relevant to muon g-2.

Findings

Favored parameter region for muon g-2 can be tested with larger kaon samples.

Enhanced photon rejection improves sensitivity to gauge boson signals.

Potential to constrain or discover $L_{}-L_{ au}$ gauge interactions.

Abstract

A model with $L_{\mu} -L_{\tau}$ gauge symmetry is the least constrained model as a resolution to the disagreement of the muon anomalous magnetic moment between the theoretical predictions and the experimental results. In this paper, we discuss how well the $L_{\mu} - L_{\tau}$ model can be constrained by looking for decays of the charged kaon associated with a $L_{\mu}-L_{\tau}$ gauge boson. More concretely, we consider searches for single muon tracks from the decays of stopped charged kaon as in the E949 experiment. In our conservative estimation, we find that the favored parameter region for the muon anomalous magnetic moment can be tested by using a $10$ times larger number of the stopped charged kaons and about a $100$ times better photon rejection rate than the E949 experiment.