Search for the Standard Model Higgs boson decay to $\mu^{+}\mu^{-}$ with the ATLAS detector

TL;DR

This paper reports a search for the Higgs boson decay to muon pairs using ATLAS data, setting upper limits on the decay rate consistent with the Standard Model predictions.

Contribution

It provides the first experimental upper limit on the Higgs to muon pair decay at 7 and 8 TeV collision energies, constraining the Higgs coupling to second-generation fermions.

Findings

No significant excess observed in the muon pair mass spectrum.

Upper limit on the Higgs to muon decay branching ratio is 1.5×10⁻³ at 95% confidence level.

Results are consistent with Standard Model predictions.

Abstract

A search is reported for Higgs boson decay to $\mu^{+}\mu^{-}$ using data with an integrated luminosity of $24.8~\rm{fb}^{-1}$ collected with the ATLAS detector in $pp$ collisions at $\sqrt{s}$=7 and 8 TeV at the CERN Large Hadron Collider. The observed dimuon invariant mass distribution is consistent with the Standard Model background-only hypothesis in the 120-150 GeV search range. For a Higgs boson with a mass of 125.5 GeV, the observed (expected) upper limit at the 95 % confidence level is 7.0 (7.2) times the Standard Model expectation. This corresponds to an upper limit on the branching ratio BR($H \rightarrow \mu^+\mu^-$) of $1.5\times10^{-3}$.