Bonn 2020 – scientific programme

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T: Fachverband Teilchenphysik

T 79: Experimental methods IV

T 79.4: Talk

Thursday, April 2, 2020, 17:15–17:30, H-ÜR 1

sPlot technique: Comparison of error correction methods in unbinned maximum likelihood fits with sWeighted events — Peter Buchholz, Siddardha Chelluri, Mazuza Ghneimat, •Tim-Philip Hücking, Iskander Ibragimov, and Wolfgang Walkowiak — Universität Siegen, Germany

The sPlot technique is used in HEP to e.g. separate signal and background events in control variable distributions on a statistical basis. Extracting sWeights from a fit to a discriminating variable distribution, the signal and background distributions of the control variable are constructed by weighting the events with the sWeights. If an unbinned maximum likelihood fit is performed on such a distribution, the covariance matrix returned by the minimization package Minuit needs to be corrected, as in the case of fits to weighted events in general. Different methods to correct the uncertainties in this case are discussed based on pseudo experiments, performed in RooFit.