Charged-lepton-flavor violation in $|\Delta S|=1$ hyperon decays

Abstract

Studies of lepton-flavor violation in strangeness-changing ($|\Delta S|=1$) transitions have a~long tradition in the kaon sector where they provide some of the strongest limits on physics beyond the standard model. Recent hints of violation of lepton-flavor universality in $B$-meson decays have revived interest in lepton-flavor violation as the two phenomena appear simultaneously in many extensions of the standard model. At the same time, the LHCb experiment has produced new results for the hyperon process $\Sigma^+\to p\mu^+\mu^-$ and may be in a position to study other rare hyperon decay modes. With this in mind, we investigate $|\Delta S|=1$ hyperon decays into different-flavor lepton pairs $e^\pm\mu^\mp$ in a model-independent manner and contrast the coverage of parameter space that can be achieved with what is known from kaon modes. We include a comparison with selected two-body leptonic decays of charged mesons, with $K\to \pi\nu\bar\nu$ modes, with $\mu\to e$ conversion, and with lepton-flavor violating decays of other neutral mesons, all of which constrain the same parameter space in a complementary~way.