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CMS-SMP-16-007 ; CERN-EP-2018-126
Measurement of the weak mixing angle using the forward-backward asymmetry of Drell-Yan events in pp collisions at 8 TeV
Eur. Phys. J. C 78 (2018) 701
Abstract: A measurement is presented of the effective leptonic weak mixing angle (${\sin^2\theta^{\ell}_{\text{eff}}} $) using the forward-backward asymmetry of Drell-Yan lepton pairs ($\mu\mu$ and ee) produced in proton-proton collisions at $\sqrt{s} = $ 8 TeV at the CMS experiment of the LHC. The data correspond to integrated luminosities of 18.8 and 19.6 fb$^{-1}$ in the dimuon and dielectron channels, respectively, containing 8.2 million dimuon and 4.9 million dielectron events. With more events and new analysis techniques, including constraints obtained on the parton distribution functions from the measured forward-backward asymmetry, the statistical and systematic uncertainties are significantly reduced relative to previous CMS measurements. The extracted value of ${\sin^2\theta^{\ell}_{\text{eff}}} $ from the combined dilepton data is ${\sin^2\theta^{\ell}_{\text{eff}}} = $ 0.23101 $\pm$ 0.00036 (stat) $\pm$ 0.00018 (syst) $\pm$ 0.00016 (theo) $\pm$ 0.00031 (parton distributions in proton) $ = $ 0.23101 $\pm$ 0.00053.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1:
The dependence of $ {A_\text {FB}} $ on $ {m_{\ell \ell}} $ in dimuon events generated using PYTHIA 8.212 [15] and the LO NNPDF3.0 [16] PDFs for dimuon rapidities of $ | y_{\ell \ell} | < $ 2.4. The distributions for the total production (${{\mathrm {q}} {\overline {\mathrm {q}}}}$) and the different channels are given on the left, overlaid with results based on Eq. (6), using the definition of $ {A_\text {FB}} ^\text {true}({m_{\ell \ell}})$ for the known quark direction. The middle panel gives the diluted ${A_\text {FB}}$ using instead the direction of the dilepton boost, and the right panel shows the diluted ${A_\text {FB}}$ in $ | y_{\ell \ell} | $ bins of 0.4 for all channels.

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Figure 1-a:
The dependence of $ {A_\text {FB}} $ on $ {m_{\ell \ell}} $ in dimuon events generated using PYTHIA 8.212 [15] and the LO NNPDF3.0 [16] PDFs for dimuon rapidities of $ | y_{\ell \ell} | < $ 2.4. This panel shows the distributions for the total production (${{\mathrm {q}} {\overline {\mathrm {q}}}}$) and the different channels, overlaid with results based on Eq. (6), using the definition of $ {A_\text {FB}} ^\text {true}({m_{\ell \ell}})$ for the known quark direction.

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Figure 1-b:
The dependence of $ {A_\text {FB}} $ on $ {m_{\ell \ell}} $ in dimuon events generated using PYTHIA 8.212 [15] and the LO NNPDF3.0 [16] PDFs for dimuon rapidities of $ | y_{\ell \ell} | < $ 2.4. This panel gives the diluted ${A_\text {FB}}$ using instead the direction of the dilepton boost.

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Figure 1-c:
The dependence of $ {A_\text {FB}} $ on $ {m_{\ell \ell}} $ in dimuon events generated using PYTHIA 8.212 [15] and the LO NNPDF3.0 [16] PDFs for dimuon rapidities of $ | y_{\ell \ell} | < $ 2.4. This panel shows the diluted ${A_\text {FB}}$ in $ | y_{\ell \ell} | $ bins of 0.4 for all channels.

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Figure 2:
Dimuon (left) and dielectron (right) mass distributions in three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4 (upper), 0.8 $ < | y_{\ell \ell} | < $ 1.2 (middle), and 1.6 $ < | y_{\ell \ell} | < $ 2.0 (lower).

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Figure 2-a:
Dimuon mass distributions in one of the three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4.

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Figure 2-b:
Dielectron mass distributions in one of the three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4.

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Figure 2-c:
Dimuon mass distributions in one of the three representative bins in rapidity: 0.8 $ < | y_{\ell \ell} | < $ 1.2.

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Figure 2-d:
Dielectron mass distributions in one of the three representative bins in rapidity: 0.8 $ < | y_{\ell \ell} | < $ 1.2.

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Figure 2-e:
Dimuon mass distributions in one of the three representative bins in rapidity: 1.6 $ < | y_{\ell \ell} | < $ 2.0.

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Figure 2-f:
Dielectron mass distributions in one of the three representative bins in rapidity: 1.6 $ < | y_{\ell \ell} | < $ 2.0.

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Figure 3:
The muon (left) and electron (right) ${\cos\theta ^{*}}$ distributions in three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4 (upper), 0.8 $ < | y_{\ell \ell} | < $ 1.2 (middle), and 1.6 $ < | y_{\ell \ell} | < $ 2.0 (lower). The small contributions from backgrounds are included in the predictions.

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Figure 3-a:
The muon ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4. The small contributions from backgrounds are included in the predictions.

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Figure 3-b:
The electron ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: $ | y_{\ell \ell} | < $ 0.4. The small contributions from backgrounds are included in the predictions.

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Figure 3-c:
The muon ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: 0.8 $ < | y_{\ell \ell} | < $ 1.2. The small contributions from backgrounds are included in the predictions.

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Figure 3-d:
The electron ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: 0.8 $ < | y_{\ell \ell} | < $ 1.2. The small contributions from backgrounds are included in the predictions.

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Figure 3-e:
The muon ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: 1.6 $ < | y_{\ell \ell} | < $ 2.0. The small contributions from backgrounds are included in the predictions.

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Figure 3-f:
The electron ${\cos\theta ^{*}}$ distributions in one of three representative bins in rapidity: 1.6 $ < | y_{\ell \ell} | < $ 2.0. The small contributions from backgrounds are included in the predictions.

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Figure 4:
Comparison between data and best-fit ${A_\text {FB}}$ distributions in the dimuon (upper) and dielectron (lower) channels. The best-fit ${A_\text {FB}}$ value in each bin is obtained via linear interpolation between two neighboring templates. Here, the templates are based on the central prediction of the NLO NNPDF3.0 PDFs. The error bars represent the statistical uncertainties in the data.

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Figure 4-a:
Comparison between data and best-fit ${A_\text {FB}}$ distributions in the dimuon channel. The best-fit ${A_\text {FB}}$ value in each bin is obtained via linear interpolation between two neighboring templates. Here, the templates are based on the central prediction of the NLO NNPDF3.0 PDFs. The error bars represent the statistical uncertainties in the data.

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Figure 4-b:
Comparison between data and best-fit ${A_\text {FB}}$ distributions in the dielectron channel. The best-fit ${A_\text {FB}}$ value in each bin is obtained via linear interpolation between two neighboring templates. Here, the templates are based on the central prediction of the NLO NNPDF3.0 PDFs. The error bars represent the statistical uncertainties in the data.

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Figure 5:
Distribution in ${A_\text {FB}}$ as a function of dilepton mass, integrated over rapidity (left), and in six rapidity bins (right) for $ {\sin^2\theta ^{\ell}_{\text {eff}}} =$ 0.23120 in POWHEG. The solid lines in the bottom panel correspond to six changes at $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ around the central value, corresponding to: $ \pm$ 0.00040, $ \pm $ 0.00080, and $ \pm $ 0.00120. The dashed lines refer to the ${A_\text {FB}}$ predictions for 100 NNPDF3.0 replicas. The shaded bands illustrate the standard deviation in the NNPDF3.0 replicas.

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Figure 5-a:
Distribution in ${A_\text {FB}}$ as a function of dilepton mass, integrated over rapidity for $ {\sin^2\theta ^{\ell}_{\text {eff}}} =$ 0.23120 in POWHEG. The solid lines in the bottom panel correspond to six changes at $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ around the central value, corresponding to: $ \pm$ 0.00040, $ \pm $ 0.00080, and $ \pm $ 0.00120. The dashed lines refer to the ${A_\text {FB}}$ predictions for 100 NNPDF3.0 replicas. The shaded bands illustrate the standard deviation in the NNPDF3.0 replicas.

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Figure 5-b:
Distribution in ${A_\text {FB}}$ as a function of dilepton mass, in six rapidity bins for $ {\sin^2\theta ^{\ell}_{\text {eff}}} =$ 0.23120 in POWHEG. The solid lines in the bottom panel correspond to six changes at $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ around the central value, corresponding to: $ \pm$ 0.00040, $ \pm $ 0.00080, and $ \pm $ 0.00120. The dashed lines refer to the ${A_\text {FB}}$ predictions for 100 NNPDF3.0 replicas. The shaded bands illustrate the standard deviation in the NNPDF3.0 replicas.

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Figure 6:
The upper panel in each figure shows a scatter plot in $\chi ^2_ {\text {min}} $ v.s. the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for 100 NNPDF replicas in the muon channel (upper left), electron channel (upper right), and their combination (below). The corresponding lower panels have the projected distributions in the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for the nominal (open circles) and weighted (solid circles) replicas.

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Figure 6-a:
The upper panel in each figure shows a scatter plot in $\chi ^2_ {\text {min}} $ v.s. the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for 100 NNPDF replicas in the muon channel. The corresponding lower panel has the projected distributions in the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for the nominal (open circles) and weighted (solid circles) replicas.

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Figure 6-b:
The upper panel in each figure shows a scatter plot in $\chi ^2_ {\text {min}} $ v.s. the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for 100 NNPDF replicas in the electron channel. The corresponding lower panel has the projected distributions in the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for the nominal (open circles) and weighted (solid circles) replicas.

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Figure 6-c:
The upper panel in each figure shows a scatter plot in $\chi ^2_ {\text {min}} $ v.s. the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for 100 NNPDF replicas in the combination of the muon and electron channels. The corresponding lower panel has the projected distributions in the best-fit ${\sin^2\theta ^{\ell}_{\text {eff}}}$ for the nominal (open circles) and weighted (solid circles) replicas.

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Figure 7:
The extracted values of ${\sin^2\theta ^{\ell}_{\text {eff}}}$ in the muon and electron channels, and their combination. The horizontal bars include statistical, experimental, and PDF uncertainties. The PDF uncertainties are obtained both without (left) and with (right) using the Bayesian $\chi ^2$ weighting.

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Figure 7-a:
The extracted values of ${\sin^2\theta ^{\ell}_{\text {eff}}}$ in the muon and electron channels, and their combination. The horizontal bars include statistical, experimental, and PDF uncertainties. The PDF uncertainties are obtained both without using the Bayesian $\chi ^2$ weighting.

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Figure 7-b:
The extracted values of ${\sin^2\theta ^{\ell}_{\text {eff}}}$ in the muon and electron channels, and their combination. The horizontal bars include statistical, experimental, and PDF uncertainties. The PDF uncertainties are obtained both with using the Bayesian $\chi ^2$ weighting.

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Figure 8:
Extracted values of $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ from the dimuon data for different sets of PDFs with the nominal (left) and $\chi ^2$-reweighted (right) replicas. The horizontal error bars include contributions from statistical, experimental, and PDF uncertainties.

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Figure 8-a:
Extracted values of $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ from the dimuon data for different sets of PDFs with the nominal replicas. The horizontal error bars include contributions from statistical, experimental, and PDF uncertainties.

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Figure 8-b:
Extracted values of $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ from the dimuon data for different sets of PDFs with the $\chi ^2$-reweighted replicas. The horizontal error bars include contributions from statistical, experimental, and PDF uncertainties.

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Figure 9:
Comparison of the measured $ {\sin^2\theta ^{\ell}_{\text {eff}}} $ in the muon and electron channels and their combination, with previous LEP, SLD, Tevatron, and LHC measurements. The shaded band corresponds to the combination of the LEP and SLD measurements.
Tables

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Table 1:
Summary of statistical uncertainties in ${\sin^2\theta ^{\ell}_{\text {eff}}}$. The statistical uncertainties in the lepton-selection efficiency and in the calibration coefficients in data are included in the estimates.

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Table 2:
Summary of experimental systematic uncertainties in ${\sin^2\theta ^{\ell}_{\text {eff}}}$.

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Table 3:
Summary of the theoretical uncertainties for the dimuon and dielectron channels, as discussed in the text.

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Table 4:
The central value and the PDF uncertainty in the measured ${\sin^2\theta ^{\ell}_{\text {eff}}}$ in the muon and electron channels, and their combination, obtained without and with constraining PDFs using Bayesian $\chi ^2$ reweighting.
Summary
The effective leptonic mixing angle, ${\sin^2\theta^{\ell}_{\text{eff}}} $, has been extracted from measurements of the mass and rapidity dependence of the forward-backward asymmetries ${A_\text{FB}}$ in Drell-Yan $\mu\mu$ and ee production. As a baseline model, we use the POWHEG event generator for the inclusive ${\mathrm{p}}{\mathrm{p}}\to\mathrm{Z}/\gamma\to\ell\ell$ process at leading electroweak order, where the weak mixing angle is interpreted through the improved Born approximation as the effective angle incorporating higher-order corrections. With more data and new analysis techniques, including precise lepton-momentum calibration, angular event weighting, and additional constraints on PDFs, the statistical and systematic uncertainties are significantly reduced relative to previous CMS measurements. The combined result from the dielectron and dimuon channels is ${\sin^2\theta^{\ell}_{\text{eff}}} = $ 0.23101 $\pm$ 0.00036 (stat) $\pm$ 0.00018 (syst) $\pm$ 0.00016 (theo) $\pm$ 0.00031 (PDF) or summing the uncertainties in quadrature, $ {\sin^2\theta^{\ell}_{\text{eff}}} = $ 0.23101 $\pm$ 0.00053. A comparison of the extracted $ {\sin^2\theta^{\ell}_{\text{eff}}} $ with previous results from LEP, SLC, Tevatron, and LHC, shown in Fig. 9, indicates consistency with the mean of the most precise LEP and SLD results, as well as with the other measurements.
References
1 J. C. Collins and D. E. Soper Angular distribution of dileptons in high-energy hadron collisions PRD 16 (1977) 2219
2 D. Y. Bardin, W. F. L. Hollik, and G. Passarino Reports of the working group on precision calculations for the z resonance technical report, CERN
3 D. \relax Yu. Bardin et al. ZFITTER v.6.21: A semianalytical program for fermion pair production in $ \Pe^+\Pe^- $ annihilation CPC 133 (2001) 229 hep-ph/9908433
4 The ALEPH Collaboration, the DELPHI Collaboration, the L3 Collaboration, the OPAL Collaboration, the SLD Collaboration, the LEP Electroweak Working Group, the SLD Electroweak and Heavy Flavour Groups Precision electroweak measurements on the $ Z $ resonance PR 427 (2006) 257 hep-ex/0509008
5 D0 Collaboration Measurement of the forward-backward charge asymmetry and extraction of $ \sin^2\theta_\mathrm{W}^{\mathrm{eff}} $ in $ {\mathrm{p}}\bar{{\mathrm{p}}}\rightarrow\mathrm{Z}/\gamma^*+X \rightarrow \Pe^+\Pe^- + X $ events produced at $ \sqrt{s} = $ 1.96 TeV PRL 101 (2008) 191801 0804.3220
6 D0 Collaboration Measurement of $ \sin^2\theta_{\rm eff}^{\ell} $ and $ Z $-light quark couplings using the forward-backward charge asymmetry in $ p\bar{p} \to Z/\gamma^{*} \to e^{+}e^{-} $ events with $ {\cal L}= $ 5.0 fb$ ^{-1} $ at $ \sqrt{s}= $ 1.96 TeV PRD 84 (2011) 012007 1104.4590
7 CMS Collaboration Measurement of the weak mixing angle with the Drell-Yan process in proton-proton collisions at the LHC PRD 84 (2011) 112002 CMS-EWK-11-003
1110.2682
8 CDF Collaboration Indirect measurement of $ \sin^2\theta_W (M_W) $ using $ e^+e^- $ pairs in the Z-boson region with $ p\bar{p} $ collisions at a center-of-momentum energy of 1.96 TeV PRD 88 (2013) 072002 1307.0770
9 CDF Collaboration Indirect measurement of $ \sin^2 \theta_W $ (or $ M_W $) using $ \mu^+\mu^- $ pairs from $ \gamma^*/Z $ bosons produced in $ p\bar{p} $ collisions at a center-of-momentum energy of 1.96 TeV PRD 89 (2014) 072005 1402.2239
10 D0 Collaboration Measurement of the effective weak mixing angle in $ p\bar{p}\rightarrow Z/\gamma^{*}\rightarrow e^{+}e^{-} $ events PRL 115 (2015) 041801 1408.5016
11 ATLAS Collaboration Measurement of the forward-backward asymmetry of electron and muon pair-production in $ pp $ collisions at $ \sqrt{s} = $ 7 TeV with the ATLAS detector JHEP 09 (2015) 049 1503.03709
12 LHCb Collaboration Measurement of the forward-backward asymmetry in $ Z/\gamma^{\ast} \rightarrow \mu^{+}\mu^{-} $ decays and determination of the effective weak mixing angle JHEP 11 (2015) 190 1509.07645
13 CDF Collaboration Measurement of $ \sin^2\theta^{\rm lept}_{\rm eff} $ using $ e^+e^- $ pairs from $ \gamma^*/Z $ bosons produced in $ p\bar{p} $ collisions at a center-of-momentum energy of 1.96 TeV PRD 93 (2016) 112016 1605.02719
14 CDF and D0 Collaborations Tevatron Run II combination of the effective leptonic electroweak mixing angle Submitted to PRD 1801.06283
15 T. Sjostrand et al. An Introduction to PYTHIA 8.2 CPC 191 (2015) 159 1410.3012
16 NNPDF Collaboration Parton distributions for the LHC Run II JHEP 04 (2015) 040 1410.8849
17 CMS Collaboration The CMS experiment at the CERN LHC JINST 3 (2008) S08004 CMS-00-001
18 CMS Collaboration Performance of CMS muon reconstruction in $ pp $ collision events at $ \sqrt{s} = $ 7 TeV JINST 7 (2012) P10002 CMS-MUO-10-004
1206.4071
19 CMS Collaboration Performance of electron reconstruction and selection with the CMS detector in proton-proton collisions at $ \sqrt{s} = $ 8 TeV JINST 10 (2015) P06005 CMS-EGM-13-001
1502.02701
20 CMS Collaboration The CMS trigger system JINST 12 (2017) P01020 CMS-TRG-12-001
1609.02366
21 CMS Collaboration Particle-flow reconstruction and global event description with the CMS detector JINST 12 (2017) P10003 CMS-PRF-14-001
1706.04965
22 D. Bourilkov Photon-induced background for dilepton searches and measurements in pp collisions at 13 TeV 1606.00523
23 S. Alioli, P. Nason, C. Oleari, and E. Re NLO vector-boson production matched with shower in POWHEG JHEP 07 (2008) 060 0805.4802
24 P. Nason A new method for combining NLO QCD with shower Monte Carlo algorithms JHEP 11 (2004) 040 hep-ph/0409146
25 S. Frixione, P. Nason, and C. Oleari Matching NLO QCD computations with parton shower simulations: the POWHEG method JHEP 11 (2007) 070 0709.2092
26 S. Alioli, P. Nason, C. Oleari, and E. Re A general framework for implementing NLO calculations in shower Monte Carlo programs: the POWHEG BOX JHEP 06 (2010) 043 1002.2581
27 H.-L. Lai et al. New parton distributions for collider physics PRD 82 (2010) 074024 1007.2241
28 T. Sjostrand, S. Mrenna, and P. Skands PYTHIA 6.4 physics and manual JHEP 05 (2006) 026 hep-ph/0603175
29 CMS Collaboration Study of the underlying event at forward rapidity in pp collisions at $ \sqrt{s} = $ 0.9, 2.76, and 7 TeV JHEP 04 (2013) 072 CMS-FWD-11-003
1302.2394
30 CMS Collaboration Event generator tunes obtained from underlying event and multiparton scattering measurements EPJC 76 (2016) 155 CMS-GEN-14-001
1512.00815
31 N. Davidson et al. Universal interface of TAUOLA: Technical and physics documentation CPC 183 (2012) 821 1002.0543
32 J. Pumplin et al. New generation of parton distributions with uncertainties from global QCD analysis JHEP 07 (2002) 012 hep-ph/0201195
33 GEANT4 Collaboration GEANT4 --- a simulation toolkit NIMA 506 (2003) 250
34 CMS Collaboration Measurement of the differential cross section and charge asymmetry for inclusive $ \mathrm {p}\mathrm {p}\rightarrow \mathrm {W}^{\pm}+X $ production at $ {\sqrt{s}} = $ 8 TeV EPJC 76 (2016) 469 CMS-SMP-14-022
1603.01803
35 A. Bodek et al. Extracting muon momentum scale corrections for hadron collider experiments EPJC 72 (2012) 2194 1208.3710
36 Y. Li and F. Petriello Combining QCD and electroweak corrections to dilepton production in the framework of the FEWZ simulation code PRD 86 (2012) 094034 1208.5967
37 M. Czakon and A. Mitov Top++: a program for the calculation of the top-pair cross-section at hadron colliders CPC 185 (2014) 2930 1112.5675
38 E. Mirkes and J. Ohnemus $ W $ and $ Z $ polarization effects in hadronic collisions PRD 50 (1994) 5692 hep-ph/9406381
39 A. Bodek A simple event weighting technique for optimizing the measurement of the forward-backward asymmetry of Drell-Yan dilepton pairs at hadron colliders EPJC 67 (2010) 321 0911.2850
40 B. Efron Bootstrap methods: Another look at the jackknife Ann. Statist. 7 (1979) 1
41 U. Baur et al. Electroweak radiative corrections to neutral current Drell-Yan processes at hadron colliders PRD 65 (2002) 033007 hep-ph/0108274
42 CMS Collaboration CMS luminosity based on pixel cluster counting --- Summer 2013 update CMS-PAS-LUM-13-001 CMS-PAS-LUM-13-001
43 K. Hamilton, P. Nason, and G. Zanderighi MINLO: multi-scale improved NLO JHEP 10 (2012) 155 1206.3572
44 P. Golonka and Z. Was PHOTOS Monte Carlo: A precision tool for QED corrections in $ Z $ and $ W $ decays EPJC 45 (2006) 97 hep-ph/0506026
45 E. Barberio and Z. W\cas PHOTOS: A universal Monte Carlo for QED radiative corrections. Version 2.0 CPC 79 (1994) 291
46 N. Davidson, T. Przedzinski, and Z. Was PHOTOS interface in C++: Technical and Physics Documentation CPC 199 (2016) 86 1011.0937
47 W. T. Giele and S. Keller Implications of hadron collider observables on parton distribution function uncertainties PRD 58 (1998) 094023 hep-ph/9803393
48 N. Sato, J. F. Owens, and H. Prosper Bayesian reweighting for global fits PRD 89 (2014) 114020 1310.1089
49 A. Bodek, J. Han, A. Khukhunaishvili, and W. Sakumoto Using Drell-Yan forward-backward asymmetry to reduce PDF uncertainties in the measurement of electroweak parameters EPJC 76 (2016) 115 1507.02470
50 S. Dulat et al. New parton distribution functions from a global analysis of quantum chromodynamics PRD 93 (2016) 033006 1506.07443
51 L. A. Harland-Lang, A. D. Martin, P. Motylinski, and R. S. Thorne Parton distributions in the LHC era: MMHT 2014 PDFs EPJC 75 (2015) 204 1412.3989
52 S. Carrazza et al. An unbiased Hessian representation for Monte Carlo PDFs EPJC 75 (2015) 369 1505.06736
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