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| CMS-SMP-16-002 ; CERN-EP-2016-169 | ||
| Measurement of the WZ production cross section in pp collisions at $\sqrt{s} = $ 13 TeV | ||
| CMS Collaboration | ||
| 23 July 2016 | ||
| Phys. Lett. B 766 (2017) 268 | ||
| Abstract: The WZ production cross section in proton-proton collisions at $\sqrt{s} = $ 13 TeV is measured with the CMS experiment at the LHC using a data sample corresponding to an integrated luminosity of 2.3 fb$^{-1}$. The measurement is performed in the leptonic decay modes ${\mathrm{ W }\mathrm{Z}} \to \ell\nu\ell'\ell'$, where $\ell$, $\ell' = \mathrm{ e }$, $\mu$. The measured cross section for the range 60 $ < m_{{\ell'\ell'}} < $ 120 GeV is $\sigma({\mathrm{ p }\mathrm{ p }} \to {\mathrm{ W }\mathrm{Z}} =$ 39.9 $\pm$ 3.2 (stat) ${}^{+2.9}_{-3.1 }$ (syst) $\pm$ 0.4 (theory) $\pm$ 1.3 (lumi) pb, consistent with the standard model prediction. | ||
| Links: e-print arXiv:1607.06943 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; | ||
| Figures | |
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Figure 1:
(a) Distribution of the reconstructed $\ell '\ell '$ pair mass summed for all decay channels with the $m_{\ell '\ell '}$ selection extended to 60-120 GeV. (b) Distribution of the $\ell \ell '\ell '$ reconstructed mass summed for all decay channels with the $m_{3\ell } > $ 100 GeV selection requirement removed. (c) The transverse mass of the lepton from the W boson and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. (d) The transverse mass of the three leptons and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in the signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 1-a:
(a) Distribution of the reconstructed $\ell '\ell '$ pair mass summed for all decay channels with the $m_{\ell '\ell '}$ selection extended to 60-120 GeV. (b) Distribution of the $\ell \ell '\ell '$ reconstructed mass summed for all decay channels with the $m_{3\ell } > $ 100 GeV selection requirement removed. (c) The transverse mass of the lepton from the W boson and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. (d) The transverse mass of the three leptons and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in the signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 1-b:
(a) Distribution of the reconstructed $\ell '\ell '$ pair mass summed for all decay channels with the $m_{\ell '\ell '}$ selection extended to 60-120 GeV. (b) Distribution of the $\ell \ell '\ell '$ reconstructed mass summed for all decay channels with the $m_{3\ell } > $ 100 GeV selection requirement removed. (c) The transverse mass of the lepton from the W boson and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. (d) The transverse mass of the three leptons and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in the signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 1-c:
(a) Distribution of the reconstructed $\ell '\ell '$ pair mass summed for all decay channels with the $m_{\ell '\ell '}$ selection extended to 60-120 GeV. (b) Distribution of the $\ell \ell '\ell '$ reconstructed mass summed for all decay channels with the $m_{3\ell } > $ 100 GeV selection requirement removed. (c) The transverse mass of the lepton from the W boson and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. (d) The transverse mass of the three leptons and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in the signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 1-d:
(a) Distribution of the reconstructed $\ell '\ell '$ pair mass summed for all decay channels with the $m_{\ell '\ell '}$ selection extended to 60-120 GeV. (b) Distribution of the $\ell \ell '\ell '$ reconstructed mass summed for all decay channels with the $m_{3\ell } > $ 100 GeV selection requirement removed. (c) The transverse mass of the lepton from the W boson and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. (d) The transverse mass of the three leptons and the $ {E_{\mathrm {T}}^{\text {miss}}} $ system. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in the signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 2:
(a) Distribution of the number of jets with $ {p_{\mathrm {T}}} > $ 30 GeV in the event. (b) Transverse momentum of the lepton associated with the W boson. (c) Transverse momentum of selected Z boson candidates. (d) Transverse momentum of selected W boson candidates. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 2-a:
(a) Distribution of the number of jets with $ {p_{\mathrm {T}}} > $ 30 GeV in the event. (b) Transverse momentum of the lepton associated with the W boson. (c) Transverse momentum of selected Z boson candidates. (d) Transverse momentum of selected W boson candidates. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 2-b:
(a) Distribution of the number of jets with $ {p_{\mathrm {T}}} > $ 30 GeV in the event. (b) Transverse momentum of the lepton associated with the W boson. (c) Transverse momentum of selected Z boson candidates. (d) Transverse momentum of selected W boson candidates. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 2-c:
(a) Distribution of the number of jets with $ {p_{\mathrm {T}}} > $ 30 GeV in the event. (b) Transverse momentum of the lepton associated with the W boson. (c) Transverse momentum of selected Z boson candidates. (d) Transverse momentum of selected W boson candidates. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
png pdf |
Figure 2-d:
(a) Distribution of the number of jets with $ {p_{\mathrm {T}}} > $ 30 GeV in the event. (b) Transverse momentum of the lepton associated with the W boson. (c) Transverse momentum of selected Z boson candidates. (d) Transverse momentum of selected W boson candidates. Solid symbols represent the data with statistical uncertainty, while histograms represent the expected WZ signal and backgrounds. Uncertainties in signal and background yields include experimental systematic, theoretical, and integrated luminosity uncertainties in addition to the statistical uncertainty. The background shapes are taken from simulation or data, as described in the text. |
| Tables | |
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Table 1:
The contributions of each systematic uncertainty source to the final uncertainty in the cross section measurement. The integrated luminosity as well as the PDF and scale uncertainties are reported separately while the other uncertainties are combined into a single systematic uncertainty. |
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Table 2:
The expected yields of WZ events and the estimated yields of background events, consisting of the prompt leptons estimated from simulation and nonprompt from a data driven method, compared to the number of observed events for each decay channel. |
| Summary |
| The WZ production cross section in proton-proton collisions at $\sqrt{s} = $ 13 TeV has been measured with the CMS experiment at the LHC using a data sample corresponding to an integrated luminosity of 2.3 fb$^{-1}$. The measurement is performed in the leptonic decay modes ${\mathrm{ W }\mathrm{Z}} \to \ell\nu\ell'\ell'$, where $\ell$, $\ell' = \mathrm{ e }$, $\mu$. The measured fiducial ${\mathrm{ W }\mathrm{Z}} \to \ell\nu\ell'\ell'$ cross section for two leptons from the Z boson decay with $p_{\mathrm{T}} > $ 20 and 10 GeV, the lepton from the W boson decay with $p_{\mathrm{T}} > $ 20 GeV, all leptons within $|\eta | < $ 2.5 , and 60 $ < m_{\ell'\ell'} < $ 120 GeV is $\sigma_{\text{fid}} ({\mathrm{ p }\mathrm{ p }} \to \mathrm{ W }\mathrm{ Z } \to \ell\nu\ell'\ell') =$ 258 $\pm$ 21 (stat) ${}^{+19}_{-20}$ (syst) $\pm$ 8 (lumi) fb. The corresponding total cross section is $\sigma({\mathrm{ p }\mathrm{ p }} \to \mathrm{ W }\mathrm{ Z }) =$ 39.9 $\pm$ 3.2 (stat) ${}^{+2.9}_{-3.1}$ (syst) $\pm$ 0.4 (theory) $\pm$ 1.3 pb for the dilepton mass range 60 $ < m_{\ell'\ell'} < $ 120 GeV. This measurement is consistent with the theoretical values of 274$^{+11}_{-8}$ (scale) $\pm$ 4 (PDF) fb for the fiducial cross section and 42.3$^{+1.4}_{-1.1}$ (scale) $\pm$ 0.6 (PDF) pb for the total cross section calculated with MCFM at NLO with NNPDF3.0 PDFs, with dynamic renormalization and factorization scales set to $\mu_R = \mu_F = m_{\mathrm{ W }\mathrm{Z}}$, and with the NNLO prediction. |
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