Evidence for the dimuon decay of the Higgs boson in pp collisions with the ATLAS detector

TL;DR

This paper reports evidence for the Higgs boson decaying into a pair of muons using ATLAS data from the LHC, combining Run 2 and Run 3 results to observe a 3.4 sigma excess over background.

Contribution

First evidence for the Higgs to muon pair decay with combined Run 2 and Run 3 ATLAS data, measuring the Higgs Yukawa coupling to second-generation fermions.

Findings

Observed 3.4 sigma excess over background

Best-fit signal strength is 1.4 ± 0.4

Provides direct measurement of Higgs coupling to muons

Abstract

A search for the dimuon decay of the Higgs boson is presented based on pp collision data recorded by ATLAS during Run 3 of the Large Hadron Collider, corresponding to an integrated luminosity of 165 fb$^{-1}$ at $\sqrt{s} = 13.6$ TeV. To enhance the sensitivity, the results are combined with those from Run 2. An excess of events over the background is observed with a significance of $3.4 \sigma$ ($2.5 \sigma$ expected). The best-fit signal strength is $\mu = 1.4\pm0.4$. This result provides evidence for the $H \to \mu\mu$ decay with ATLAS data and offers a direct probe of the Higgs-boson Yukawa coupling to second-generation fermions.