CMS-PAS-SMP-16-009

CMS-PAS-SMP-16-009
Measurement of the differential Drell-Yan cross section in proton-proton collisions at $\sqrt{s} = $ 13 TeV
CMS Collaboration
August 2016

Abstract: We present measurement of the differential Drell-Yan cross section $\mathrm{d}\sigma/\mathrm{d}m$. The analysis is based on the full 2015 dataset, corresponding to an integrated luminosity of 2.8 fb$^{-1}$ of proton-proton collision data collected by the CMS detector. The cross section measurement is reported in the dimuon invariant mass range from 15 to 3000 GeV. The results are corrected to the full phase space and the effects of final state radiation are also taken into account. The data are compared to perturbative QCD predictions. The results are found to be in good agreement with the standard model predictions.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ;

Figures	Summary	Additional Figures	References	CMS Publications

Figures
png pdf	Figure 1: The observed dimuon invariant mass spectra within the detector acceptance. The EW contributions indicate the $\mathrm {DY} \rightarrow \tau ^+\tau ^-$, diboson, and W+jets productions. Error bars are statistical only.
png pdf	Figure 2: The DY acceptance (A), efficiency ($\varepsilon $) and their product per invariant mass bin.
png pdf	Figure 3: Summary of the systematic uncertainties for $\mathrm{d}\sigma / \mathrm{d} m $ measurement. The ``Total Systematic'' is a quadratic sum of all systematic uncertainty sources except for the Acc.+PDF.
png pdf	Figure 4: Result of the DY differential cross section measurement for full phase space with FSR correction as a function of dimuon invariant mass compared to the NNLO theoretical prediction of FEWZ (red) and the NLO prediction of MadGraph5-aMCatNLO (green). Both NNPDF3.0 PDF set is used for the theoretical calculation. In the middle and bottom plots, the band with red colour denotes total uncertainty which is the combination of statistical, systematical, theoretical, and luminosity uncertainties. The band with purple colour denotes the statistical uncertainty only.
png pdf	Figure 5: Comparison between the experimental results for fiducial cross section without FSR correction and the NLO theoretical prediction using MadGraph5-aMCatNLO. On the bottom plot, the band with red colour denotes total uncertainty which is the combination of statistical, systematical, and luminosity uncertainty. The band with purple colour denotes the statistical uncertainty only.

Summary

In summary, this note presented results of the measurement of the Drell-Yan differential cross section $\mathrm{d}\sigma/\mathrm{d}m$ in the dimuon channel in the mass range 15 $ < m < $ 3000 GeV in proton-proton collisions at $\sqrt{s} = $ 13 TeV. The measurement is based on the dataset corresponding to an integrated luminosity of 2.8 fb$^{-1}$. The measurement is corrected for detector resolution correction resulting in event migration between mass bins, efficiency caused by the difference between data and MC simulation, acceptance to take into account the coverage of CMS detector, and FSR effects pronounced mostly below the Z peak. The results are in good agreement with the SM theoretical predictions at NNLO predictions calculated with FEWZ and NLO predictions calculated with aMCatNLO.

Additional Figures
png pdf	Additional Figure 1: The response matrix from simulation for detector resolution effect.
png pdf	Additional Figure 2: The response matrix from simulation for FSR effect.
png pdf	Additional Figure 3: Fraction of backgrounds as a function of dimuon invariant mass. The fraction is determined by the ratio of the number of backgrounds estimated to the number of data after event selection respectively.

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