Higgs rare and exotic decays

TL;DR

This paper reviews recent searches for rare and exotic Higgs boson decays at the LHC, highlighting evidence for the $H\rightarrow \ell\ell \gamma$ decay with a significance of 3.2 sigma.

Contribution

It reports new experimental results from ATLAS and CMS on multiple rare Higgs decay channels, including evidence for the $H\rightarrow \ell\ell \gamma$ decay.

Findings

Evidence for $H\rightarrow \ell\ell \gamma$ with 3.2 sigma significance

Searches for $H\rightarrow aa$ in three final states

Searches for lepton-flavour violating decays $H\rightarrow \mu\tau / e\tau$

Abstract

Several recent searches for exotic and rare decays of the Standard Model Higgs boson with the ATLAS and CMS detectors are presented. The searches are performed on $\sqrt{s}$=13 TeV proton-proton collisions data collected at the LHC between 2015 and 2018. The topics covered include searches for the Higgs boson decays into two pseudoscalars, $H\rightarrow aa$, in three different final states, $2b2\mu$, $4b$ and $2\mu2\tau$, search for lepton-flavour violating Higgs decays, $H\rightarrow \mu\tau / e\tau$, and search for a rare $H\rightarrow \ell\ell \gamma$ decay. ATLAS presents evidence for the $H\rightarrow \ell\ell \gamma$ rare decay, amounting to an observed significance of $3.2\sigma$.