Lepton Flavor-Violating Higgs Decays Mediated by Ultralight Gauge Boson

TL;DR

This paper investigates lepton-flavor violating Higgs decays mediated by an ultralight gauge boson, using experimental bounds to set limits on nonstandard decay processes and analyzing various observables for potential signals.

Contribution

It introduces a model linking lepton-flavor violation to an ultralight gauge boson and derives experimental bounds on related Higgs decay channels.

Findings

Established upper limits on nonstandard Higgs decays involving $ar{ u}_i u_j ext{ and } ar{ u}_i u_j ext{ channels.

Analyzed lepton energy spectra, Dalitz plots, and asymmetries to identify potential signatures.

Provided constraints consistent with CMS and ATLAS bounds.

Abstract

We present an analysis of the lepton-flavor violating decay of the Higgs boson mediated by an ultralight gauge boson, $\chi$. Our analysis matches a model generating the lepton flavor-violating interaction $\bar{\ell}_i\ell_j\chi$ at tree level with an effective field theory, safeguarding a physical massless $\chi$-boson limit of the observables. By utilizing the upper bounds on $H\to\ell_i \bar\ell_j$ decays from CMS and ATLAS Collaborations, we establish an indirect upper limit on the nonstandard decay $H\to\ell_i \bar\ell_j\chi$. The analysis encompasses various observables such as the lepton energy spectrum, Dalitz plot distribution, and Lepton Charge and Forward-Backward Asymmetries.