M. Dubinin

Four-Fermion Production in Electron-Positron Collisions /

This report summarises the results of the four-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the calculation of four-fermion processes in electron-positron collisions at LEP-2 centre-of-mass energies are presented, concentrating on predictions for four main reactions: W-pair production, visible photons in four-fermion events, single-W production and Z-pair production. Based on a comparison of results derived within different approaches, theoretical uncertainties on these predictions are established.

Search for neutral Higgs bosons decaying to tau pairs in pp collisions at √s=7 TeV

A search for neutral Higgs bosons decaying to tau pairs at a center-of-mass energy of 7 TeV is performed using a dataset corresponding to an integrated luminosity of 4.6 fb−1 recorded by the CMS experiment at the LHC. The search is sensitive to both the standard model Higgs boson and to the neutral Higgs bosons predicted by the minimal supersymmetric extension of the standard model (MSSM). No excess of events is observed in the tau-pair invariant-mass spectrum. For a standard model Higgs boson in the mass range of 110–145 GeV upper limits at 95% confidence level (CL) on the production cross section are determined. We exclude a Higgs boson with mH = 115 GeV with a production cross section 3.2 times of that predicted by the standard model. In the MSSM, upper limits on the neutral Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, mA, sets stringent new bounds in the parameter space, excluding at 95% CL values of tan β as low as 7.1 at mA =160 GeV. Submitted to Physics Letters B ∗See Appendix A for the list of collaboration members ar X iv :1 20 2. 40 83 v1 [ he pex ] 1 8 Fe b 20 12

Comparison of the Z/γ ∗ + jets to γ + jets cross sections in pp collisions at √s= 8 TeV

A bstractA comparison of the differential cross sections for the processes Z/γ* + jets and photon (γ)+jets is presented. The measurements are based on data collected with the CMS detector at s=8

Search for associated production of dark matter with a Higgs boson decaying to bb¯ or γγ at √s = 13 TeV

\sqrt{s}=8

Measurement of the ratio of the production cross sections times branching fractions of B^±_c → J/ψπ^± and B^± → J/ψK^± and B(B^±_c → J/ψπ^±π^±π^∓)/B(B^±_c → J/ψπ^±) in pp collisions at √s = 7 TeV

TeV corresponding to an integrated luminosity of 19.7 fb−1. The differential cross sections and their ratios are presented as functions of pT. The measurements are also shown as functions of the jet multiplicity. Differential cross sections are obtained as functions of the ratio of the Z/γ*pT to the sum of all jet transverse momenta and of the ratio of the Z/γ*pT to the leading jet transverse momentum. The data are corrected for detector effects and are compared to simulations based on several QCD calculations.

Standard model processes

A bstractMeasurements are presented of Wγγ and Zγγ production in proton-proton collisions. Fiducial cross sections are reported based on a data sample corresponding to an integrated luminosity of 19.4 fb−1 collected with the CMS detector at a center-of-mass energy of 8 TeV. Signal is identified through the W → ℓν and Z → ℓℓ decay modes, where ℓ is a muon or an electron. The production of Wγγ and Zγγ, measured with significances of 2.6 and 5.9 standard deviations, respectively, is consistent with standard model predictions. In addition, limits on anomalous quartic gauge couplings in Wγγ production are determined in the context of a dimension-8 effective field theory.