Accounting for jet response induced MET backgrounds to new physics at the ATLAS experiment at CERN’s LHC

Detector mis-modelling or hardware problems may cause an excess of Missing Transverse Energy (MET) to be inferred in physics events recorded in ATLAS, leading to higher than expected backgrounds for new physics. In particular, non-Gaussian tails in the MET distribution are unlikely to be well modelled in Monte Carlo simulations. To account for this, a technique has been established to improve the background predictions derived from Monte Carlo simulations. This is done using a correction derived through comparison of control samples in data and Monte Carlo simulation. Two different control samples are used to create the correction, giving a range of predictions for the shape of the MET tail and aiding the calculation of systematic errors. This technique is then applied to several samples which are potential backgrounds to new physics which give detector signatures which include MET.