Search for a charged Higgs boson decaying into top and bottom quarks in proton-proton collisions at 13TeV in events with electrons or muons

A search is presented for a charged Higgs boson heavier than the top quark and decaying into a top-bottom quark-antiquark pair. Events are selected by the presence of a single isolated charged lepton (electron or muon) or an opposite sign dilepton (electron or muon) pair, categorized according to the jet multiplicity and the number of jets containing a b-hadron decay, and multivariate techniques are used to enhance the signal-background discrimination in each category. This search is based on proton-proton collision data collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 $\mathrm{fb}^{-1}$. The data are compatible with the standard model, and $95\%$ CL upper limits of 9.6--0.01 pb are set on the product of the charged Higgs boson production cross section and the branching fraction to top-bottom quark-antiquark pair, with mass from 200 GeV to 3 TeV. The upper limits are interpreted in different minimal supersymmetric extensions of the standard model.