CMS-SMP-20-012

CMS-SMP-20-012 ; CERN-EP-2021-111
Measurements of the electroweak diboson production cross sections in proton-proton collisions at $\sqrt{s} = $ 5.02 TeV using leptonic decays
CMS Collaboration
2 July 2021
Phys. Rev. Lett. 127 (2021) 191801
Abstract: The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302 pb$^{-1}$. Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as $\sigma_{WW}=$ 37.0$^{+5.5}_{-5.2}$ (stat) $^{+2.7}_{-2.6}$ (syst) pb, $\sigma_{{\mathrm{W} \mathrm{Z}} }=$ 6.4$^{+2.5}_{-2.1}$ (stat) $^{+0.5}_{-0.3}$ (syst) pb, and $\sigma_{\mathrm{ZZ} }= $ 5.3 $^{+2.5}_{-2.1}$ (stat) $^{+0.5}_{-0.4}$ (syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.
Links: e-print arXiv:2107.01137 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ;

Figures & Tables	Summary	Additional Figures & Tables	References	CMS Publications

Figures
png pdf	Figure 1: Distribution of the dilepton ${p_{\mathrm {T}}}$ in the WW signal region (left). Events from DY, conversions, and diboson processes are grouped into the 'Others' category. Distribution of the W boson transverse mass in the WZ 3$\ell $ signal region (right). Events from conversions, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Figure 1-a: Distribution of the dilepton ${p_{\mathrm {T}}}$ in the WW signal region. Events from DY, conversions, and diboson processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Figure 1-b: Distribution of the W boson transverse mass in the WZ 3$\ell $ signal region. Events from conversions, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Figure 2: Results obtained in this analysis and other diboson production cross section measurements at different center-of-mass energies for the CMS [11,12,13,14,15,16,17,18], ATLAS [2,3,4,5,6,7,8,9,10], CDF [54,55], and D0 [56,57,58] Collaborations are presented, and compared with the NNLO QCD $\times $ NLO EW and NLO predictions from matrix. The vertical error bars represent the uncertainty in the measured cross section.

Tables
png pdf	Table 1: Expected event yields in the WWSR and observed number of events. The uncertainties correspond to the statistical and systematic component, respectively.
png pdf	Table 2: Expected event yields for the signal and total background in the WZ and ZZ SRs, and observed number of events. The uncertainties correspond to the statistical and systematic component, respectively.

Summary

The diboson production cross sections are measured for the first time at a new energy, 5.02 TeV, using data collected with the CMS detector corresponding to an integrated luminosity of 302 pb$^{-1}$. The analysis is performed in the leptonic decays of the W and Z bosons with at least two leptons in the final state. The measured total cross sections are consistent with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.

Additional Figures
png pdf	Additional Figure 1: Distribution of the dilepton invariant mass in the WW signal region. Events from DY, conversions, and diboson processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Additional Figure 2: Distribution of the Z boson ${p_{\mathrm {T}}}$ in the WZ 3$\ell $ signal region. Events from conversions, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Additional Figure 3: Distributions of the Z boson ${p_{\mathrm {T}}}$, and the invariant mass of the ZZ system in the ZZ 4$\ell $ signal region. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Additional Figure 3-a: Distribution of the Z boson ${p_{\mathrm {T}}}$ in the ZZ 4$\ell $ signal region. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Additional Figure 3-b: Distribution of the invariant mass of the ZZ system in the ZZ 4$\ell $ signal region. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png pdf	Additional Figure 4: Distributions of the ${{p_{\mathrm {T}}} ^\text {miss}}$, and the dilepton invariant mass in the ZZ 2$\ell $2$\nu $ signal region. Events from top, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png	Additional Figure 4-a: Distribution of the ${{p_{\mathrm {T}}} ^\text {miss}}$ in the ZZ 2$\ell $2$\nu $ signal region. Events from top, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).
png	Additional Figure 4-b: Distribution of the dilepton invariant mass in the ZZ 2$\ell $2$\nu $ signal region. Events from top, and DY processes are grouped into the 'Others' category. The vertical error bars represent the statistical uncertainty in the data and the shaded band the uncertainty in the prediction. The signal contributions are scaled to the measured cross sections (postfit).

Additional Tables
png pdf	Additional Table 1: Expected event yields in the WZ 3$\ell $ and WZ 2$\mu $ss signal regions, and observed number of events. The uncertainties correspond to the statistical and systematic component, respectively.
png pdf	Additional Table 2: Expected event yields in the ZZ 4$\ell $ (left) and ZZ 2$\ell $2$\nu $ (right) signal regions, and observed number of events. The uncertainties correspond to the statistical and systematic component, respectively.
png pdf	Additional Table 3: Sources of systematic uncertainties and their input values.
png pdf	Additional Table 4: Measured total cross sections and their corresponding uncertainties.The predictions from matrix (at NNLO QCD $\times $ NLO EW) are also included.

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