Exclusive rare Higgs decays into lepton pair and light mesons

TL;DR

This paper investigates rare Higgs decays into lepton pairs and light mesons within the standard model, predicting very small branching ratios and analyzing decay distributions, highlighting potential for future experimental exploration.

Contribution

It provides detailed predictions for branching ratios and decay distributions of rare Higgs decays into leptons and light mesons, emphasizing their significance for understanding the standard model and probing new physics.

Findings

Branching ratios predicted between 10^{-8} and 10^{-5}.

Differential dilepton invariant mass and angular distributions analyzed.

Rare decays could be valuable for future high-precision experiments.

Abstract

Exclusive rare Higgs decays into lepton pair plus one light hadron, such as $h\to \rho^0(\omega)\ell\bar{\ell}$, $h\to \pi^0\ell\bar{\ell}$, $h\to \pi^+ (K^+)\ell^-\bar{\nu}_\ell$, and $h\to \rho^+(K^{*+})\ell^-\bar{\nu}_\ell$, have been explored in the standard model. Decay amplitudes are dominantly from the Higgs couplings to gauge bosons and to charged leptons, and their branching ratios are predicted in the range of $10^{-8}\sim 10^{-5}$. We have also analyzed the differential dilepton invariant mass and angular distributions of $h\to \rho^0 \ell^+\ell^-$ decays. It will be challenging to search for these rare processes. Nevertheless, experimental studies of them, in particular, $h\to \rho^0\ell^+\ell^-$ with $\ell=e,\mu$, might be interesting both to help deepen our understanding of the standard model and to probe new physics beyond the standard model in the future high-precision experiments.