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Author Jorda, Clara
Source CERN Document Server
Content type Text
File Format PDF
Date Created 2011-11-03
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Physics ♦ Modern physics ♦ Technology ♦ Engineering & allied operations ♦ Applied physics
Subject Keyword General ♦ Detectors and Experimental Techniques
Abstract A measurement of the W$\gamma$, Z$\gamma$, and W$^{+}$W$^{-}$ di-boson production in proton-proton collisions at $\sqrt{s} = 7$ TeV is presented. Results are based on data sample recorded by CMS experiment at LHC, corresponding to an integrated luminosity of $36$ $pb^{-1}$. The electron and muon decay channels of the W and Z are used. In the case of W$\gamma$ and Z$\gamma$ the total cross sections are measured for photon transverse energy $E_T^{\gamma} > 10$ GeV and spatial separation from charged lepton in the plane of pseudorapidity and azimuthal angle $\Delta R(l,\gamma) > 0.7$, with an additional dilepton invariant mass requirement of $M_{ll} > 50$ GeV for the Z$\gamma$ process. W$^{+}$W$^{-}$ candidates are selected as final states with two oppositely charged leptons and large missing transverse energy. The following cross sections times braching fraction values are found: $\sigma($W$\gamma + X)$ x $B/$W$\rightarrow l\nu)$ = 56.3 $\pm$ 5.0 (stat.) $\pm$ 5.0 (syst.) $\pm$ 2.3 (lumi.) pb and $\sigma($Z$\gamma + X)$ x $B($W$\rightarrow ll)$ = 9.4 $\pm$ 1.0 (stat.) $\pm$ 0.6 (syst.) $\pm$ 0.4 (lumi.) pb. The W$^{+}$W$^{-}$ cross section is measured to be 41.1 $\pm$ 15.3 (stat.) $\pm$ 5.8 (syst.) $\pm$ 4.5 (lumi.) pb. These measurements are in agreement with standard model predictions. The first limit on anomalous WW$\gamma$, ZZ$\gamma$ and Z$\gamma\gamma$ trilinear gauge couplings at $\sqrt{s} = 7$ TeV are set. }
Description Presented at: 23rd Rencontres de Blois on "Particle Physics and Cosmology", Blois, Loire Valley, France, 29 May - 3 Jun 2011
Collaboration with: CMS
Learning Resource Type Article
Publisher Date 2011-01-01
Rights License Preprint: (License: CC-BY-4.0)
Page Count 5