Measurement of the differential t/t production cross section at 13 TeV with CMS in the all-hadronic boosted regime

An inclusive and differential measurement of the t/t production cross section in the all-hadronic channel is presented here, using data from 13 TeV pp collisions, collected by the CMS detector at the LHC in 2016, corresponding to an integrated luminosity of 37 fb−1 . The analysis has been performed in the boosted regime, characterized by high-pT top quarks whose decay products are reconstructed, due to the large Lorentz boost, into two wide jets. The inclusive t/t production cross section has been measured to be σt/t = 572 ± 14(stat) ± 118(syst) ± 14(lumi) pb, a value quite lower than the theoretical prediction. An overestimation of the POWHEG + PYTHIA 8 Monte Carlo selection efficiency could explain this effect. The detector-level differential cross section is then measured as a function of some variables of interest and it is compared to the theoretical predictions. Finally, an unfolding procedure is performed in order to remove detector effects and to extrapolate the differential cross section measurement to the full parton-level phase space.