Search for displaced muonic lepton jets from light Higgs boson decay in proton-proton collisions at sqrt(s) = 7 TeV with the ATLAS detector

TL;DR

This paper searches for displaced muon pairs from long-lived neutral particles possibly originating from Higgs boson decays, using ATLAS data at 7 TeV, setting limits on new physics scenarios involving hidden sectors.

Contribution

It introduces a novel search for displaced muonic lepton jets from Higgs decays to long-lived particles at the LHC.

Findings

No excess observed over Standard Model background

Limits set on Higgs decay to long-lived hidden-sector particles

Constraints depend on the particles' mean lifetime

Abstract

A search is performed for collimated muon pairs displaced from the primary vertex produced in the decay of long-lived neutral particles in proton-proton collisions at sqrt(s) = 7 TeV centre-of-mass energy, with the ATLAS detector at the LHC. In a 1.9 fb-1 event sample collected during 2011, the observed data are consistent with the Standard Model background expectations. Limits on the product of the production cross section and the branching ratio of a Higgs boson decaying to hidden-sector neutral long-lived particles are derived as a function of the particles' mean lifetime.