Search for Displaced Muon Jets from light Higgs boson decay in proton-proton collisions at sqrt(s) = 7 Tev with the ATLAS detector

A search is presented for collimated muon pairs produced in the decay of long-lived neutral particles in proton-proton collisions at sqrt(s) = 7 TeV center of mass energy, with the ATLAS detector at the LHC. In a sample of 1.94 fb−1 of collision events 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 fraction of a Higgs boson decaying to Hidden Valley neutral long-lived particles are derived as a function of the particles’ mean c*tau.