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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...
Autor principal: | |
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Publicado: |
2010
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Materias: | |
Acceso en línea: | http://cds.cern.ch/record/1279615 |
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. |
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