CMSPASSMP16012  
Search for anomalous couplings in semileptonic WW and WZ decays at $ \sqrt{s} = $ 13 TeV  
CMS Collaboration  
August 2016  
Abstract: The increased center of mass energy of the LHC Run II allows for a much larger reach to study possible deviations from the standard model in a generic manner, using an effective field theory approach. In this analysis we constrain additional operators that would lead to anomalous WW$\gamma$ or WWZ couplings by studying events with one W boson decaying to an electron or muon and neutrino and one W or Z boson decaying hadronically. The study uses a sample of protonproton collisions collected with the CMS experiment at a centerofmass energy of $\sqrt{s}=$ 13 TeV corresponding to an integrated luminosity of 2.3 fb$^{1}$. Using diboson mass distributions we derive 95% confidence intervals for the anomalous coupling parameters $\frac{c_{\mathrm{WWW}}}{\Lambda ^2}$ ($ [9.46 , 9.42]$ TeV$^{2}$), $\frac{c_\mathrm{W}}{\Lambda ^2}$ ($ [12.6, 12.0]$ TeV$^{2}$) and $\frac{c_\mathrm{B}}{\Lambda ^2}$ ($ [56.1, 55.4]$ TeV$^{2}$), in agreement with standard model expectations.  
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; 
Figures & Tables  Summary  Additional Figures  References  CMS Publications 

Figures  
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Figure 1a:
Comparison between data and simulation of the ${M_\mathrm {pruned}}$ (a,b) and $M_\mathrm{WV}$ (c,d) distributions in the ${\mathrm {t}\overline {\mathrm {t}}}$ control region. The electron channel is shown on (a,c), while the muon channel is shown on (b,d). Details concerning the systematic uncertainties can be found in section 6. 
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Figure 1b:
Comparison between data and simulation of the ${M_\mathrm {pruned}}$ (a,b) and $M_\mathrm{WV}$ (c,d) distributions in the ${\mathrm {t}\overline {\mathrm {t}}}$ control region. The electron channel is shown on (a,c), while the muon channel is shown on (b,d). Details concerning the systematic uncertainties can be found in section 6. 
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Figure 1c:
Comparison between data and simulation of the ${M_\mathrm {pruned}}$ (a,b) and $M_\mathrm{WV}$ (c,d) distributions in the ${\mathrm {t}\overline {\mathrm {t}}}$ control region. The electron channel is shown on (a,c), while the muon channel is shown on (b,d). Details concerning the systematic uncertainties can be found in section 6. 
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Figure 1d:
Comparison between data and simulation of the ${M_\mathrm {pruned}}$ (a,b) and $M_\mathrm{WV}$ (c,d) distributions in the ${\mathrm {t}\overline {\mathrm {t}}}$ control region. The electron channel is shown on (a,c), while the muon channel is shown on (b,d). Details concerning the systematic uncertainties can be found in section 6. 
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Figure 2a:
Result of the template fit to the ${M_\mathrm {pruned}}$distributions, electron channel on (a), muon channel on (b). 
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Figure 2b:
Result of the template fit to the ${M_\mathrm {pruned}}$distributions, electron channel on (a), muon channel on (b). 
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Figure 3a:
Comparison of the $M_\mathrm{WV}$ distribution in the data and background estimate for the electron (a,c) and muon channel (b,d) in the WW (a,b) and WZcategory (c,d). The pink line represents the sum of the backgrounds and a signal with an aTGC value of $c_{\mathrm{WWW}}=$ 12 TeV$^{2}$. Each figure also shows the difference between data and the SM prediction, divided by the statistical uncertainty of the datapoints. 
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Figure 3b:
Comparison of the $M_\mathrm{WV}$ distribution in the data and background estimate for the electron (a,c) and muon channel (b,d) in the WW (a,b) and WZcategory (c,d). The pink line represents the sum of the backgrounds and a signal with an aTGC value of $c_{\mathrm{WWW}}=$ 12 TeV$^{2}$. Each figure also shows the difference between data and the SM prediction, divided by the statistical uncertainty of the datapoints. 
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Figure 3c:
Comparison of the $M_\mathrm{WV}$ distribution in the data and background estimate for the electron (a,c) and muon channel (b,d) in the WW (a,b) and WZcategory (c,d). The pink line represents the sum of the backgrounds and a signal with an aTGC value of $c_{\mathrm{WWW}}=$ 12 TeV$^{2}$. Each figure also shows the difference between data and the SM prediction, divided by the statistical uncertainty of the datapoints. 
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Figure 3d:
Comparison of the $M_\mathrm{WV}$ distribution in the data and background estimate for the electron (a,c) and muon channel (b,d) in the WW (a,b) and WZcategory (c,d). The pink line represents the sum of the backgrounds and a signal with an aTGC value of $c_{\mathrm{WWW}}=$ 12 TeV$^{2}$. Each figure also shows the difference between data and the SM prediction, divided by the statistical uncertainty of the datapoints. 
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Figure 4a:
Two dimensional limits on the aTGCparameters. Shown are the expected contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{W}}{\Lambda ^2}$ (a), $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (b) and $\frac {c_\mathrm{W}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (c). The black line shows the region compatible with the observed data at 95% C.L. 
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Figure 4b:
Two dimensional limits on the aTGCparameters. Shown are the expected contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{W}}{\Lambda ^2}$ (a), $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (b) and $\frac {c_\mathrm{W}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (c). The black line shows the region compatible with the observed data at 95% C.L. 
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Figure 4c:
Two dimensional limits on the aTGCparameters. Shown are the expected contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{W}}{\Lambda ^2}$ (a), $\frac {c_{\mathrm{WWW}}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (b) and $\frac {c_\mathrm{W}}{\Lambda ^2}\frac {c_\mathrm{B}}{\Lambda ^2}$ (c). The black line shows the region compatible with the observed data at 95% C.L. 
Tables  
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Table 1:
Results of the fit to the ${M_\mathrm {pruned}}$ distributions in the range [40, 150] GeV. The pre and postfit yields are presented together with their constraints (prefit) and resulting total uncertainties (postfit). The W+jets contribution is allowed to float in the fit, therefore the prefit values do not have any constraint shown. The single top contribution is fixed in the fit. 
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Table 2:
Estimated normalization uncertainties in % for MC derived contributions. Uncertainties smaller than 0.05% for all processes are not listed. 
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Table 3:
Summary of background and signal yields in WW and WZcategories. Uncertainties for the singletop, diboson and ${\mathrm {t}\overline {\mathrm {t}}}$ contributions are evaluated as described in section 6, while the uncertainty on W+jets is derived from the statistical uncertainty of the ${M_\mathrm {pruned}}$fit and the fit with the alternative function. 
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Table 4:
Expected and observed limits at 95% C.L. on single anomalous couplings (other couplings set to zero). 
Summary 
While the current limits cannot supersede the results from the LHC Run I [3], it is expected that limits will substantially improve with accumulating luminosity. 
Additional Figures  
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Additional Figure 1a:
The transfer function $\alpha $ used to transport the W+jets background from the sideband to the signal region for the WWcategory (a,b) and the WZcategory (c,d) in the electron (a,c) and muonchannel (b,d). The green shaded bands show the uncertainty on $\alpha $ as obtained from the covariance matrix of the simultaneous fit in the W+jets simulation in the signal and sideband regions. The red and blue lines show the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{SB,MC}$, respectively. The left $y$axis corresponds to the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{\text{SB,MC}}$, while the right $y$axis corresponds to the transfer function $\alpha $. 
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Additional Figure 1b:
The transfer function $\alpha $ used to transport the W+jets background from the sideband to the signal region for the WWcategory (a,b) and the WZcategory (c,d) in the electron (a,c) and muonchannel (b,d). The green shaded bands show the uncertainty on $\alpha $ as obtained from the covariance matrix of the simultaneous fit in the W+jets simulation in the signal and sideband regions. The red and blue lines show the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{SB,MC}$, respectively. The left $y$axis corresponds to the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{\text{SB,MC}}$, while the right $y$axis corresponds to the transfer function $\alpha $. 
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Additional Figure 1c:
The transfer function $\alpha $ used to transport the W+jets background from the sideband to the signal region for the WWcategory (a,b) and the WZcategory (c,d) in the electron (a,c) and muonchannel (b,d). The green shaded bands show the uncertainty on $\alpha $ as obtained from the covariance matrix of the simultaneous fit in the W+jets simulation in the signal and sideband regions. The red and blue lines show the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{SB,MC}$, respectively. The left $y$axis corresponds to the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{\text{SB,MC}}$, while the right $y$axis corresponds to the transfer function $\alpha $. 
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Additional Figure 1d:
The transfer function $\alpha $ used to transport the W+jets background from the sideband to the signal region for the WWcategory (a,b) and the WZcategory (c,d) in the electron (a,c) and muonchannel (b,d). The green shaded bands show the uncertainty on $\alpha $ as obtained from the covariance matrix of the simultaneous fit in the W+jets simulation in the signal and sideband regions. The red and blue lines show the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{SB,MC}$, respectively. The left $y$axis corresponds to the functions $F_{\mathrm{W}+\text{jets}}^{\text{SR,MC}}$ and $F_{\mathrm{W}+\text{jets}}^{\text{SB,MC}}$, while the right $y$axis corresponds to the transfer function $\alpha $. 
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Additional Figure 2a:
Two dimensional limits on the aTGCparameters in the vertex parameterization. Shown are the expeted contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\lambda _{\mathrm{Z}}  \Delta \kappa _{\mathrm{Z}}$ (a), $\lambda _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$(center) and$\Delta \kappa _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$ (b). The black line shows the region compatible with the observed data at 95% C.L. 
png pdf 
Additional Figure 2b:
Two dimensional limits on the aTGCparameters in the vertex parameterization. Shown are the expeted contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\lambda _{\mathrm{Z}}  \Delta \kappa _{\mathrm{Z}}$ (a), $\lambda _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$(center) and$\Delta \kappa _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$ (b). The black line shows the region compatible with the observed data at 95% C.L. 
png pdf 
Additional Figure 2c:
Two dimensional limits on the aTGCparameters in the vertex parameterization. Shown are the expeted contours for 68% C.L. (blue), 95% C.L. (green) and 99% C.L. (red), for $\lambda _{\mathrm{Z}}  \Delta \kappa _{\mathrm{Z}}$ (a), $\lambda _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$(center) and$\Delta \kappa _{\mathrm{Z}}  \Delta g_1^{\mathrm{Z}}$ (b). The black line shows the region compatible with the observed data at 95% C.L. 
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