Data-driven background estimation for the H -> tau+tau- -> lh search at 7 TeV with the ATLAS detector

Events characterised by the presence of an electron or muon, plus a hadronically decaying tau lepton and large missing transverse momentum are searched for in 7 TeV proton-proton collision data at the LHC. This event topology is of interest to the search for Higgs bosons with H -> tau+tau- -> lh (l=e,mu and h=hadronically decaying tau). The total integrated luminosity of the analysed data is 310 nb-1. Candidate events with missing transverse momentum above 20 GeV were found, 12 in the electron and 17 in the muon channels. The sum is consistent with 25+-9 expected from a data-driven background estimation and the observed visible mass distribution is agreed with the shape from the estimation. This note describes how this estimation is made, using information from data and Monte Carlo simulation.