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Measurement of the W and Z inclusive production cross sections at sqrts=7 TeV with the CMS experiment at the LHC

We present the first measurements of inclusive W and Z production cross sections in muon and electron decay channels at $\sqrt{s} = 7~\text{Te\hspace{-.08em}V}$, obtained using $198~\text{nb}^{-1}$ of pp collisions in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The m...

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Detalles Bibliográficos
Autor principal: CMS Collaboration
Publicado: 2010
Materias:
Acceso en línea:http://cds.cern.ch/record/1279615
Descripción
Sumario:We present the first measurements of inclusive W and Z production cross sections in muon and electron decay channels at $\sqrt{s} = 7~\text{Te\hspace{-.08em}V}$, obtained using $198~\text{nb}^{-1}$ of pp collisions in the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC). The measured inclusive cross sections are $\sigma(\mathrm{pp} \rightarrow \mathrm{W} + X \rightarrow \ell\nu + X) = 9.22 \pm 0.24 \mathrm{(stat.)} \pm 0.47 \mathrm{(syst.)} \pm 1.01 \mathrm{(lumi.)}$~nb, and $\sigma(\mathrm{pp} \rightarrow \mathrm{Z}(\gamma^*) + X \rightarrow \ell^+\ell^- + X) = 0.882 ^{+0.077}_{-0.073} \mathrm{(stat.)} ^{+0.042}_{-0.036} \mathrm{(syst.)} \pm 0.097 \mathrm{(lumi.)}$~nb, limited to the di-lepton invariant mass range $[60, 120]~\text{Ge\hspace{-.08em}V}$. The luminosity-independent cross section ratios are $\sigma(\mathrm{pp} \rightarrow \mathrm{W} + X \rightarrow \ell\nu + X)/\sigma(\mathrm{pp} \rightarrow \mathrm{Z}(\gamma^*) + X \rightarrow \ell^+\ell^- + X)= 10.46^{+0.99}_{-0.88} \mathrm{(stat.)} ^{+0.65}_{-0.56} \mathrm{(syst.)}$ and $\sigma(\mathrm{pp} \rightarrow \mathrm{W}^{+} + X \rightarrow \ell^{+}\nu + X)/\sigma(\mathrm{pp} \rightarrow \mathrm{W}^{-} + X \rightarrow \ell^{-}\nu + X) = 1.51 ^{+0.08}_{-0.07} \mathrm{(stat.)} \pm 0.04 \mathrm{(syst.)}$. The measured values agree with NNLO QCD cross section calculations and current parton distribution functions. We also present measurements of the W lepton asymmetry in three bins of pseudorapidity and the forward-backward asymmetry for di-muon pairs. Finally, we present the first study of hadronic jets produced in association with W~bosons.