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CMS-PAS-SMP-16-005
Measurement of the differential cross section for the production of a W ($\rightarrow \mu\nu$) boson in association with jets at $\sqrt{s} = $ 13 TeV
Abstract: A measurement of the differential cross sections for a W ($\rightarrow \mu\nu$) boson produced in association with jets is presented. The measurement is based on the 13 TeV proton-proton collisions data corresponding to an integrated luminosity of 2.5 fb$^{-1}$ recorded by the CMS detector at the CERN LHC. The cross sections are reported as a function of jet multiplicity, the jet transverse momenta, the jet rapidity, and the scalar sum of the jet transverse momenta for different jet multiplicities. The measured cross sections are compared with the predictions that include multileg leading order and next-to-leading order matrix element calculations interfaced with parton showers and a next-to-next-to-leading order calculation for W+1 jet.
Figures & Tables Summary References CMS Publications
Figures

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Figure 1-a:
Data to simulation comparison of exclusive jet multiplicity before (a) and after (b) the application of the b tag veto. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 1-b:
Data to simulation comparison of exclusive jet multiplicity before (a) and after (b) the application of the b tag veto. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 2-a:
Data to simulation comparison of exclusive (a) and inclusive (b) jet multiplicity. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 2-b:
Data to simulation comparison of exclusive (a) and inclusive (b) jet multiplicity. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 3-a:
Data to simulation comparison of $1^{st}$ (a) and $2^{nd}$ (b) jet $ {p_{\mathrm {T}}} $. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 3-b:
Data to simulation comparison of $1^{st}$ (a) and $2^{nd}$ (b) jet $ {p_{\mathrm {T}}} $. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 4:
Data to simulation comparison of $3^{rd}$ jet $ {p_{\mathrm {T}}} $. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 5-a:
Data to simulation comparison of exclusive (a) and inclusive (b) jet multiplicity in the $ {\mathrm {t}\overline {\mathrm {t}}} $-enriched control sample. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 5-b:
Data to simulation comparison of exclusive (a) and inclusive (b) jet multiplicity in the $ {\mathrm {t}\overline {\mathrm {t}}} $-enriched control sample. The diboson samples (WW, WZ, and ZZ) are represented by VV. The error bars on the ratio panel represent the statistical uncertainty of the data and simulated signal sample.

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Figure 6-a:
The differential cross section measurement for the exclusive and inclusive jet multiplicities, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. Black circular markers with the grey hatched band represent the unfolded data measurement and its total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled band around MG-aMC FxFx prediction represents its theoretical uncertainty including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 6-b:
The differential cross section measurement for the exclusive and inclusive jet multiplicities, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. Black circular markers with the grey hatched band represent the unfolded data measurement and its total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled band around MG-aMC FxFx prediction represents its theoretical uncertainty including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 7-a:
The differential cross section measurement for the leading three jets' transverse momenta, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet transverse momentum. Black circular markers with the grey hatched band represent the unfolded data measurement and its total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 7-b:
The differential cross section measurement for the leading three jets' transverse momenta, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet transverse momentum. Black circular markers with the grey hatched band represent the unfolded data measurement and its total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 7-c:
The differential cross section measurement for the leading three jets' transverse momenta, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet transverse momentum. Black circular markers with the grey hatched band represent the unfolded data measurement and its total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 8-a:
The differential cross section measurement for the leading three jets' absolute rapidities, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet absolute rapidity. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 8-b:
The differential cross section measurement for the leading three jets' absolute rapidities, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet absolute rapidity. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 8-c:
The differential cross section measurement for the leading three jets' absolute rapidities, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the first leading jet absolute rapidity. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties including both statistical and systematical uncertainties. The lower panels show the ratios of the prediction to the unfolded data.

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Figure 9-a:
The differential cross section measurement for $ {H_{\mathrm {T}}} $ for inclusive jet multiplicities 1-3, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the jets $ {H_{\mathrm {T}}} $ for one inclusive jet. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties incuding both statistical and systematical uncertainties. The lower panels show the ratio of the prediction to the unfolded data.

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Figure 9-b:
The differential cross section measurement for $ {H_{\mathrm {T}}} $ for inclusive jet multiplicities 1-3, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the jets $ {H_{\mathrm {T}}} $ for one inclusive jet. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties incuding both statistical and systematical uncertainties. The lower panels show the ratio of the prediction to the unfolded data.

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Figure 9-c:
The differential cross section measurement for $ {H_{\mathrm {T}}} $ for inclusive jet multiplicities 1-3, compared to the predictions of MG-aMC FxFx and MG-aMC, where latter denoted as MG in the legends. The NNLO prediction for W+1-jet is included in the jets $ {H_{\mathrm {T}}} $ for one inclusive jet. Black circular markers with the grey hatched band represent the unfolded data measurement and total experimental uncertainty. MG-aMC is given only with its statistical uncertainty. Color filled bands around MG-aMC FxFx and NNLO predictions represent their theoretical uncertainties incuding both statistical and systematical uncertainties. The lower panels show the ratio of the prediction to the unfolded data.
Tables

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Table 1:
Number of events in data and simulation as a function of the exclusive jet multiplicity after the implementation of b tag veto. QCD background is estimated using a data-driven method. The diboson samples (WW, WZ, and ZZ) are represented by VV.
Summary
The first measurement of the differential cross sections for a W boson produced in association with jets in proton-proton collisions at a centre-of-mass energy of 13 TeV is presented. The collisions data used correspond to an integrated luminosity of 2.5 fb$^{-1}$ with 25 ns bunch crossing and were collected with the CMS detector during 2015 at the LHC. The differential cross sections are measured using the muon decay mode of the W boson as a function of the exclusive and the inclusive jet multiplicities up to a multiplicity of five, the jet $p_{\mathrm{T}}$ and rapidity $|y|$ for the three leading jets, and the jet $H_{\mathrm{T}}$ for a multiplicity up to at least three jets. The data distributions are corrected for all detector effects by means of regularised unfolding and compared with the particle level predictions by MG-aMC FxFx at NLO accuracy and by MG-aMC tree level at LO accuracy. The measured data is compared with a calculation at NNLO accuracy for W+1-jet production. The predictions are able to describe data well on the exclusive and inclusive jet multiplicities within the uncertainties. The predictions are in good agreement with data on the jet $p_{\mathrm{T}}$ spectra. The jet $|y|$ and $H_{\mathrm{T}}$ spectra are well modeled by both MG-aMC FxFx merged NLO prediction for all inclusive jet multiplicities and NNLO calculation for one inclusive jet. Overall, MG-aMC tree level slightly underestimates data on the observables.
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Compact Muon Solenoid
LHC, CERN