Search for a light charged Higgs boson in top quark decays in pp collisions at root s=7 TeV

Results are presented on a search for a light charged Higgs boson that can be produced in the decay of the top quark t -> H(+)b and which, in turn, decays into tau(+)nu(tau). The analysed data correspond to an integrated luminosity of about 2 fb(-1) recorded in proton-proton collisions at root s = 7 TeV by the CMS experiment at the LHC. The search is sensitive to the decays of the top quark pairs t (t) over bar -> H(+/-)W(-/+)b (b) over bar and t (t) over bar -> H +/- H -/+ b (b) over bar. Various final states have been studied separately, all requiring presence of a tau lepton from H+ decays, missing transverse energy, and multiple jets. Upper limits on the branching fraction B(t -> H(+)b) in the range of 2-4% are established for charged Higgs boson masses between 80 and 160 GeV, under the assumption that B(H+ -> tau(+)nu(tau)) = 1

Shape, transverse size, and charged-hadron multiplicity of jets in pp collisions at sqrt(s) = 7 TeV

Measurements of jet characteristics from inclusive jet production in proton-proton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 inverse picobarns. The mean charged hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-kT algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo generators