Search for new physics in a Monojet plus missing transverse energy final state with ATLAS

A monojet plus large missing transverse energy final state is of interest as it is foreseen as a signal in several beyond SM physics scenarios. The search for new physics in this event topology is performed in pp collisions at √s= 7 TeV with ATLAS. The analysis is model independent and 3 kinematic regions are explored. Results from the analysis are interpreted in terms of the ADD extra dimensions model. As with every search, a major challenge is the understanding and suppression of SM backgrounds. W/Z+jet production constitutes the dominant contribution to the background for this signal. The irreducible background for this signal is Z+jet production where the Z decays to a neutrino-antineutrino pair giving rise to large missing transverse energy. The estimate for all W/Z+jet backgrounds is done using data-driven methods. Latest results from the analysis are presented using about 1 inverse femtobarn of 2011 data.