Unfolding W + jets Event Distributions at 7 TeV with the ATLAS Detector

This report presents a study on the unfolding of the exclusive jet multiplicity distribution in W + jets events generated by Alpgen and Sherpa Monte Carlo event generators. After implementing the particle level event selection on Monte Carlo, two dierent unfolding procedures are tested, the bin-by-bin method and the iterative Bayesian approach by D'Agostini. For the bin-by-bin method the correction factor for both Alpgen and Sherpa is computed. With the iterative Bayesian method a closure test in Alpgen was performed in order to validate the procedure and gaining an estimate of the systematic eects of unfolding. The migration matrix and the result of this closure test are presented.