Reconstructing the 125 GeV SM Higgs Boson Through $\ell\bar{\ell}\gamma$

TL;DR

This paper reanalyzes the Higgs boson decay to lepton pairs with an additional photon, showing that radiative decays could be a significant and observable channel for confirming the 125 GeV Higgs in current LHC data.

Contribution

It provides a detailed analysis of Higgs radiative decays to lepton pairs with photons, highlighting their potential as observable signals for the Standard Model Higgs.

Findings

Radiative decay branching fractions are about two-thirds of the muon pair decay.

Photon and lepton energies above 1 GeV are significant for detection.

Radiative processes mainly originate from Z-boson conversion, reducing background noise.

Abstract

To ascertain the new boson with mass near 125 {GeV} observed recently by ATLAS and CMS Collaborations to be the Standard Model Higgs, and to determine its intrinsic properties, more measurements on its various decay channels are still necessary. In this work we reanalyze the processes of the Standard Model Higgs radiative decays to lepton pairs. We find that when photon and leptons are hard, that is possessing energies larger than 1 {GeV}, the branching fractions of $H\rightarrow \ell\bar{\ell}\gamma (\ell=e~or~\mu)$ processes are about two-thirds of the $H\rightarrow\mu^+\mu^-$ process. Since the lepton-pair yields of the radiative processes mainly come from the Z-boson conversion, which will greatly suppress the backgrounds, we believe the signal should be observable in presently accumulated data or in the next run of the LHC experiment, provided the Standard Model Higgs is indeed light.