Bi-Weekly IIHE Internal Seminar: Thomas Reis, "Background Estimations for a Z' Search"

Thursday 24 Nov 2011, 11:00 → 11:45 Europe/Brussels

Large Seminary Room (IIHE)

A Z' is a hypothetical elementary particle which is predicted by different theories beyond the standard model. I it exists it should reveal itself as a heavy resonance in the Drell-Yan spectrum in the high mass region above the Z peak as it decays in the same double leptonic channels as the Z boson. A search for such a resonance involving also members of the IIHE is performed with the CMS detector at the LHC. The seminar deals with the invariant mass spectrum of a Z' search and in particular with the estimation of two of the backgrounds that are measured directly from the data. One is the QCD background of hadronic jets that are misidentified as electrons and, thus, contribute to the signal and the other is the ttbar background which, although taken from simulations in the analysis, is cross checked with events decaying in one electron and on muon to confirm the correct behaviour of the simulation. For these backgrounds details on the estimation and recent analysis results with the 2011 dataset of 4.7fb-1 of pp collisions will be shown.