Measurement of Differential Cross Sections for Z Bosons at √s = 7 TeV

EWK-10-010

Abstract

We present the first measurements of the shapes of the transverse momentum and rapidity distributions of Drell-Yan muon and electron pairs in the Z mass region (60 < M(ll) < 120 GeV) produced in proton-proton collisions at a center-of-mass energy of 7 TeV. The results were obtained using 36 pb-1 of data collected with the CMS detector at LHC. We compare the measured distributions with higher-order QCD calculations using recent parton distribution functions.

Published Results

Link to Paper

Raw Invariant Mass Distributions for Dilepton

Each plot shows the data observation compared to the signal as predicted by POWHEG on top of the background estimated from a combination of simulation and data.

Figures Caption
m_mumu.png
EPS format, PDF format
Invariant mass distributions for the muon channel
mee_ECAL_ECAL.png
EPS format, PDF format
Invariant mass distributions for events with both electrons in the ECAL
mee_ECAL_HF.png
EPS format, PDF format
Invariant mass distributions for events with one electron in the ECAL and the other in the HF

Differential Cross Section as a Function of Rapidity

Figures Caption
dsday_combined.png
EPS format, PDF format
The normalized differential cross section for Z bosons as a function of the absolute value of rapidity, combining the muon and electron channels. The error bars correspond to the experimental statistical and systematic uncertainties added in quadrature. The shaded area indicates the range of variation predicted by the POWHEG simulation for the uncertainties of the CT10 PDFs
ct10_eigenvector_compare.png
EPS format, PDF format
The change in χ2 when comparing the Z rapidity differential cross section measurement with the predictions of the NLO CT10 PDF set as each of the eigenvector input parameters is varied by plus or minus one standard deviation around its default value
mstw08_eigenvector_compare.png
EPS format, PDF format
The change in χ2 when comparing the Z rapidity differential cross section measurement with the predictions of the NLO MST2008 PDF set as each of the eigenvector input parameters is varied by 90% confidence level (CL) around its default value
herapdf15_eigenvector_compare.png
EPS format, PDF format
herapdf15_modelvar_compare.png
EPS format, PDF format
The change in χ2 when comparing the Z rapidity differential cross section measurement with the predictions of the NLO HERAPDF 1.5 PDF set as each of the eigenvector input parameters (TOP) and the model parameters is varied by one standard deviation (BOTTOM) around its default value. These together represent the full set of uncertainties in the HERAPDF 1.5 set

Differential Cross Section as a Function of Transverse Momentum

Figures Caption
dsdqt_combined.png
EPS format, PDF format
The Z boson transverse momentum distribution found from combining the muon and electron channels, compared to the predictions of the POWHEG generator interfaced with PYTHIA using the Z2 tune. The error bars correspond to the statistical and systematic uncertainties added in quadrature. The band around the theoretical prediction includes the uncertainties due to scale variations and PDFs. The horizontal error bars indicate the bin boundaries, and the data points are positioned at the center-of-gravity of the bins, based on the POWHEG prediction. The inset figure shows the low qT region on a linear scale
qt_combined_pythia.png
EPS format, PDF format
The combined electron and muon measurement of the Z boson transverse momentum distribution (points) and the predictions of four PYTHIA tunes and of POWHEG interfaced with PYTHIA using the Z2 tune (histograms). The error bars on the points represent the sum of the statistical and systematic uncertainties on the data. The lower portion of the figure shows the difference between the data and the simulation predictions divided by the uncertainty δ on the data. The green (inner) and yellow (outer) bands are the +/-1 δ and +/-2 δ experimental uncertainties
combined_fewz_normToTheory.png
EPS format, PDF format
The combined electron and muon Z boson normalized differential cross section as a function of transverse momentum (points) and the POWHEG and FEWZ predictions for qT > 20 GeV. The horizontal error bars indicate the bin boundaries and the data points are positioned at the center-of-gravity of the bins based on the POWHEG prediction. The bands in the upper plot represent the uncertainty on the predictions from factorization and renormalization scales and PDFs. The lower plot shows the ratio between the data and the theory predictions. The bands in the lower plot represent the one standard deviation combined theoretical and experimental uncertainties

Covariance Matrix

  • Computer-formatted covariance matrices as well as the individual channels and combinations uploaded to HepData, here.

-- GianPieroDiGiovanni - 22-Jan-2012

Topic attachments
I Attachment History Action Size Date Who Comment
Unknown file formateps combined_fewz_normToTheory.eps r1 manage 40.4 K 2012-01-22 - 19:25 GianPieroDiGiovanni PRD: ds/dqT muon+ele high qT comparison
PDFpdf combined_fewz_normToTheory.pdf r2 r1 manage 7.9 K 2012-01-22 - 19:25 GianPieroDiGiovanni PRD: ds/dqT muon+ele high qT comparison
PNGpng combined_fewz_normToTheory.png r2 r1 manage 40.9 K 2012-01-22 - 19:24 GianPieroDiGiovanni PRD: ds/dqT muon+ele high qT comparison
Unknown file formateps ct10_eigenvector_compare.eps r1 manage 38.3 K 2012-01-22 - 18:52 GianPieroDiGiovanni PRD: CT10 eigenvector comparison for ds/d|y|
PDFpdf ct10_eigenvector_compare.pdf r1 manage 8.4 K 2012-01-22 - 18:52 GianPieroDiGiovanni PRD: CT10 eigenvector comparison for ds/d|y|
PNGpng ct10_eigenvector_compare.png r1 manage 42.4 K 2012-01-22 - 18:52 GianPieroDiGiovanni PRD: CT10 eigenvector comparison for ds/d|y|
Unknown file formateps dsday_combined.eps r1 manage 43.1 K 2012-01-22 - 18:48 GianPieroDiGiovanni PRD: ds/d|y| muon+ele
PDFpdf dsday_combined.pdf r2 r1 manage 7.2 K 2012-01-22 - 18:47 GianPieroDiGiovanni PRD: ds/d|y| muon+ele
PNGpng dsday_combined.png r2 r1 manage 33.8 K 2012-01-22 - 18:47 GianPieroDiGiovanni PRD: ds/d|y| muon+ele
Unknown file formateps dsdqt_combined.eps r1 manage 54.8 K 2012-01-22 - 19:21 GianPieroDiGiovanni PRD: ds/dqT muon+ele
PDFpdf dsdqt_combined.pdf r1 manage 9.3 K 2012-01-22 - 19:20 GianPieroDiGiovanni PRD: ds/dqT muon+ele
PNGpng dsdqt_combined.png r1 manage 36.2 K 2012-01-22 - 19:20 GianPieroDiGiovanni PRD: ds/dqT muon+ele
Compressed Zip archivetgz ewk-10-010_hepdata.tgz r1 manage 7.1 K 2012-01-22 - 21:30 GianPieroDiGiovanni Covariance Matrices
Unknown file formateps herapdf15_eigenvector_compare.eps r1 manage 28.0 K 2012-01-22 - 19:03 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector comparison for ds/d|y|
PDFpdf herapdf15_eigenvector_compare.pdf r1 manage 5.8 K 2012-01-22 - 19:03 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector comparison for ds/d|y|
PNGpng herapdf15_eigenvector_compare.png r1 manage 29.0 K 2012-01-22 - 19:03 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector comparison for ds/d|y|
Unknown file formateps herapdf15_modelvar_compare.eps r1 manage 23.8 K 2012-01-22 - 19:05 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector + 1 sigma comparison for ds/d|y|
PDFpdf herapdf15_modelvar_compare.pdf r1 manage 5.1 K 2012-01-22 - 19:04 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector + 1 sigma comparison for ds/d|y|
PNGpng herapdf15_modelvar_compare.png r1 manage 24.3 K 2012-01-22 - 19:04 GianPieroDiGiovanni PRD: NLO HERAPDF 1.5 PDF eigenvector + 1 sigma comparison for ds/d|y|
Unknown file formateps m_mumu.eps r1 manage 129.9 K 2012-01-22 - 18:22 GianPieroDiGiovanni PRD: mass mu-mu
PDFpdf m_mumu.pdf r1 manage 12.5 K 2012-01-22 - 18:22 GianPieroDiGiovanni PRD: mass mu-mu
PNGpng m_mumu.png r1 manage 27.2 K 2012-01-22 - 18:22 GianPieroDiGiovanni PRD: mass mu-mu
Unknown file formateps mee_ECAL_ECAL.eps r1 manage 33.8 K 2012-01-22 - 18:04 GianPieroDiGiovanni PRD: mass ECAL ECAL
PDFpdf mee_ECAL_ECAL.pdf r1 manage 6.5 K 2012-01-22 - 17:44 GianPieroDiGiovanni PRD: mass ECAL ECAL
PNGpng mee_ECAL_ECAL.png r1 manage 26.1 K 2012-01-22 - 18:00 GianPieroDiGiovanni PRD: mass ECAL ECAL
Unknown file formateps mee_ECAL_HF.eps r1 manage 40.2 K 2012-01-22 - 18:21 GianPieroDiGiovanni PRD: mass ECAL HF
PDFpdf mee_ECAL_HF.pdf r1 manage 7.5 K 2012-01-22 - 18:20 GianPieroDiGiovanni PRD: mass ECAL HF
PNGpng mee_ECAL_HF.png r1 manage 29.8 K 2012-01-22 - 18:20 GianPieroDiGiovanni PRD: mass ECAL HF
Unknown file formateps mstw08_eigenvector_compare.eps r1 manage 32.7 K 2012-01-22 - 18:56 GianPieroDiGiovanni PRD: NLO MST2008 eigenvector comparison for ds/d|y|
PDFpdf mstw08_eigenvector_compare.pdf r1 manage 7.0 K 2012-01-22 - 18:56 GianPieroDiGiovanni PRD: NLO MST2008 eigenvector comparison for ds/d|y|
PNGpng mstw08_eigenvector_compare.png r1 manage 34.7 K 2012-01-22 - 18:56 GianPieroDiGiovanni PRD: NLO MST2008 eigenvector comparison for ds/d|y|
Unknown file formateps qt_combined_pythia.eps r1 manage 39.2 K 2012-01-22 - 19:23 GianPieroDiGiovanni PRD: ds/dqT muon+ele low qT comparison
PDFpdf qt_combined_pythia.pdf r2 r1 manage 7.2 K 2012-01-22 - 19:23 GianPieroDiGiovanni PRD: ds/dqT muon+ele low qT comparison
PNGpng qt_combined_pythia.png r2 r1 manage 54.9 K 2012-01-22 - 19:22 GianPieroDiGiovanni PRD: ds/dqT muon+ele low qT comparison
Edit | Attach | Watch | Print version | History: r7 < r6 < r5 < r4 < r3 | Backlinks | Raw View | WYSIWYG | More topic actions
Topic revision: r7 - 2013-03-12 - GianPieroDiGiovanni
 
    • Cern Search Icon Cern Search
    • TWiki Search Icon TWiki Search
    • Google Search Icon Google Search

    CMSPublic All webs login

This site is powered by the TWiki collaboration platform Powered by PerlCopyright & 2008-2020 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding TWiki? Send feedback