Constraint on parity-violating muonic forces

TL;DR

This paper uses kaon decay data to set limits on hypothetical parity-violating muonic forces, constraining models that could explain the proton size anomaly involving invisible or long-lived gauge bosons.

Contribution

It provides the first strong experimental constraints on exotic parity-violating muonic interactions from kaon decay observations.

Findings

Limits on parity-violating muonic gauge bosons

Constraints on models explaining the proton size anomaly

Exclusion of certain long-lived or invisibly decaying gauge bosons

Abstract

Using the nonobservance of missing mass events in the leptonic kaon decay $K \to \mu X$, we place a strong constraint on exotic parity-violating gauge interactions of the right-handed muon. By way of illustration, we apply it to an explanation of the proton size anomaly that invokes such a new force; scenarios in which the gauge boson decays invisibly or is long-lived are constrained.