Measurement of the Muon Charge Asymmetry in Inclusive $pp \to W+X$ Production at $\sqrt s =$ 7 TeV and an Improved Determination of Light Parton Distribution Functions

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev.D 90 (2014) 032004, 2014.
Inspire Record 1273570 DOI 10.17182/hepdata.65456

Measurements of the muon charge asymmetry in inclusive pp to WX production at sqrt(s) = 7 TeV are presented. The data sample corresponds to an integrated luminosity of 4.7 inverse femtobarns recorded with the CMS detector at the LHC. With a sample of more than twenty million W to mu nu events, the statistical precision is greatly improved in comparison to previous measurements. These new results provide additional constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10E-3 to 10E-1. These measurements and the recent CMS measurement of associated W + charm production are used together with the cross sections for inclusive deep inelastic ep scattering at HERA in a next-to-leading-order QCD analysis. The determination of the valence quark distributions is improved, and the strange-quark distribution is probed directly through the leading-order process g + s to W + c in proton-proton collisions at the LHC.

4 data tables

Summary of the final results for muon charge asymmetry $\mathcal{A}$ with the muon $p_{T}>25$ GeV. The first uncertainty is statistical and the second is systematic. The theoretical predictions are obtained using the FEWZ 3.1 MC tool interfaced with the NLO CT10, NNPDF2.3, HERAPDF1.5, and MSTW2008CPdeut PDF sets. The PDF uncertainty is at 68% C.L. The values are expressed as percentages.

Summary of the final results for muon charge asymmetry $\mathcal{A}$ with the muon $p_{T}>35$ GeV. The first uncertainty is statistical and the second is systematic. The theoretical predictions are obtained using the FEWZ 3.1 MC tool interfaced with the NLO CT10, NNPDF2.3, HERAPDF1.5, and MSTW2008CPdeut PDF sets. The PDF uncertainty is at 68% C.L. The values are expressed as percentages.

Covariance matrix (statistical and systematic uncertainties combined) with the muon $p_{T}>25$ GeV. The units are in $10^{-4}$.

More…

Measurement of the W-boson helicity in top-quark decays from ttbar production in lepton+jets events in pp collisions at sqrt(s)=7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
JHEP 10 (2013) 167, 2013.
Inspire Record 1249595 DOI 10.17182/hepdata.64900

The W-boson helicity fractions in top-quark decays are measured with ttbar events in the lepton+jets final state, using proton-proton collisions at a centre-of-mass energy of 7 TeV, collected in 2011 with the CMS detector at the LHC. The data sample corresponds to an integrated luminosity of 5.0 inverse femtobarns. The measured fractions of longitudinal, left-, and right-handed helicity are F0 = 0.682 +/- 0.030 (stat.) +/- 0.033 (syst.), FL = 0.310 +/- 0.022 (stat.) +/- 0.022 (syst.), and FR = 0.008 +/- 0.012 (stat.) +/- 0.014 (syst.), consistent with the standard model predictions. The measured fractions are used to probe the existence of anomalous Wtb couplings. Exclusion limits on the real components of the anomalous couplings gL, gR are also derived.

3 data tables

Measurements of the W-boson helicity fractions from the cos(theta*) (leptonic branch) distributions. The columns show the fit type, the decay channel, and the measurement of each helicity parameter, together with the statistical and systematic uncertainties. For the 3D fits, the last column presents the statistical correlation between F_0 and F_L, while for the 2D fit, total anticorrelation (F_L=1-F_0) is assumed.

Measurements of the W-boson helicity fractions from the cos(theta*) (leptonic branch) and |cos^(had) theta*| (hadronic branch) distributions. The columns show the fit type, the decay channel, and the measurement of each helicity parameter, together with the statistical and systematic uncertainties. For the 3D fits, the last column presents the statistical correlation between F_0 and F_L, while for the 2D fit, total anticorrelation (F_L=1-F_0) is assumed.

The combined helicity fractions and their uncertainties, including the type of fit performed, the channels (l=e,mu combination) and branches of the t tbar system ("l" for leptonic, cos(theta*), and "h" for hadronic, |cos^had theta*, used in the combination, as well as the total correlation between F_0 and F_L.


Measurement of the electron charge asymmetry in inclusive W production in pp collisions at sqrt(s) = 7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
Phys.Rev.Lett. 109 (2012) 111806, 2012.
Inspire Record 1118047 DOI 10.17182/hepdata.66333

A measurement of the electron charge asymmetry in inclusive pp to W + X to e nu + X production at sqrt(s) = 7 TeV is presented based on data recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 840 inverse picobarns. The electron charge asymmetry reflects the unequal production of positive and negative W bosons in pp collisions. The electron charge asymmetry is measured in bins of absolute value of electron pseudorapidity in the range of abs(eta) < 2.4. The asymmetry rises from about 0.1 to 0.2 as a function of the pseudorapidity and is measured with a relative precision better than 7%. This measurement provides new stringent constraints for parton distribution functions.

2 data tables

Summary of the measured charge asymmetry results. The first uncertainty is statistical and the second is systematic. The theoretical predictions are obtained using MCFM interfaced with four different PDF models. The PDF uncertainties are estimated using the PDF reweighting technique. All values are in units of $10^{-3}$.

Covariance matrix for the systematic uncertainties on the asymmetry. All values are given in units of $10^{-6}$.


Measurement of the Inclusive W and Z Production Cross Sections in pp Collisions at sqrt(s) = 7 TeV

The CMS collaboration Chatrchyan, Serguei ; Khachatryan, Vardan ; Sirunyan, Albert M ; et al.
JHEP 10 (2011) 132, 2011.
Inspire Record 919737 DOI 10.17182/hepdata.57964

A measurement of inclusive W and Z production cross sections in pp collisions at sqrt(s)=7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of 36 inverse picobarns. The measured inclusive cross sections are sigma(pp-> WX) B(W-> l nu) = 10.30 +/- 0.02 (stat.) +/- 0.10 (syst.) +/- 0.10 (th.) +/- 0.41 (lumi.) nb and sigma(pp -> ZX) B(Z-> l^+l^-) = 0.974 +/- 0.007 (stat.) +/- 0.007 (syst.) +/- 0.018 (th.) +/- 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120 GeV. The luminosity-independent cross section ratios are [sigma(pp->WX) B(W-> l nu)]/[sigma(pp-> ZX) B(Z->l^+l^-)] = 10.54 +/- 0.07 (stat.) +/- 0.08 (syst.) +/- 0.16 (th.) and [sigma(pp->W^+X) B(W^+ -> l^+nu)] / [sigma(pp->W^- X) B(W^- -> l^- nu)] = 1.421 +/- 0.006 (stat.) +/- 0.014 (syst.) +/- 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross section calculations based on recent parton distribution functions.

9 data tables

Measured cross sections for combined positive and negative W production.

Measured cross sections for positive W production.

Measured cross sections for negative W production.

More…

Measurements of Inclusive W and Z Cross Sections in pp Collisions at sqrt(s)=7 TeV

The CMS collaboration Khachatryan, Vardan ; Sirunyan, Albert M. ; Tumasyan, Armen ; et al.
JHEP 01 (2011) 080, 2011.
Inspire Record 881087 DOI 10.17182/hepdata.57952

Measurements of inclusive W and Z boson production cross sections in pp collisions at sqrt(s)=7 TeV are presented, based on 2.9 inverse picobarns of data recorded by the CMS detector at the LHC. The measurements, performed in the electron and muon decay channels, are combined to give sigma(pp to WX) times B(W to muon or electron + neutrino) = 9.95 \pm 0.07(stat.) \pm 0.28(syst.) \pm 1.09(lumi.) nb and sigma(pp to ZX) times B(Z to oppositely charged muon or electron pairs) = 0.931 \pm 0.026(stat.) \pm 0.023(syst.) \pm 0.102(lumi.) nb. Theoretical predictions, calculated at the next-to-next-to-leading order in QCD using recent parton distribution functions, are in agreement with the measured cross sections. Ratios of cross sections, which incur an experimental systematic uncertainty of less than 4%, are also reported.

8 data tables

Measured cross sections for combined positive and negative W production.

Measured cross sections for positive W production.

Measured cross sections for negative W production.

More…