Measurement of the differential t anti t production cross section as a function of the jet mass in fully merged top quark decays in CMS

The decay products of hadronically decaying top quarks are collimated into a single jet, if the top quarks are produced with high transverse momenta. In this case it is possible to reconstruct large jets containing a full hadronic top quark decay. The invariant mass of such jets is sensitive to the mass of the top quark itself and is calculable theoretically. A comparison to theory calculations could lead to an extraction of the top quark mass in a well defined renormalization scheme. In this contribution a measurement of the differential t anti t production cross section as a function of the jet mass is presented. The measurement is performed in the lepton+jets decay channel with data collected by the CMS detector in proton-proton collisions at a center of mass energy of 8 TeV. Events are selected with transverse jet momenta greater than 400 GeV to select fully merged top quark decays. To allow a comparison to theory calculations the data is corrected for detector effects using a regularized unfolding method.