CMS-SMP-13-008 ; CERN-EP-2017-029 | ||
Search for anomalous couplings in boosted $\mathrm{ WW/WZ }\to\ell\nu\mathrm{ q \bar{q} }$ production in proton-proton collisions at $ \sqrt{s} = $ 8 TeV | ||
CMS Collaboration | ||
17 March 2017 | ||
Phys. Lett. B 772 (2017) 21 | ||
Abstract: This Letter presents a search for new physics manifested as anomalous triple gauge boson couplings in WW and WZ diboson production in proton-proton collisions. The search is performed using events containing a W boson that decays leptonically and a W or Z boson whose decay products are merged into a single reconstructed jet. The data, collected at $ \sqrt{s} = $ 8 TeV with the CMS detector at the LHC, correspond to an integrated luminosity of 19 fb$^{-1}$. No evidence for anomalous triple gauge couplings is found and the following 95% confidence level limits are set on their values: $\lambda$ ($ [-0.011,0.011]$), $\Delta{\kappa_\gamma}$ ($ [-0.044,0.063]$), and $\Delta{g_1^{\mathrm{ Z }}}$ ($ [-0.0087,0.024]$). These limits are also translated into their effective field theory equivalents: $c_{\mathrm{ WWW }}/\Lambda^2$ ($ [-2.7,2.7]$ TeV$^{-2}$), $c_\mathrm{B}/\Lambda^2$ ($ [-14,17]$ TeV$^{-2}$), and $c_{\mathrm{ W }}/\Lambda^2$ ($ [-2.0,5.7]$ TeV$^{-2}$). | ||
Links: e-print arXiv:1703.06095 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; |
Figures | |
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Figure 1:
Post-fit distributions of the merged jet invariant mass for muons (top) and electrons (bottom) with the estimates of the relevant backgrounds. The merged jet invariant mass is plotted for all events (left), after subtraction of all components except the diboson (center), and the subsequent normalized residual or pull distributions: (data $-$ fit)/(fit uncertainty) (right). The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 1-a:
Post-fit distributions of the merged jet invariant mass for muons with the estimates of the relevant backgrounds. The merged jet invariant mass is plotted for all events. The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 1-b:
Post-fit distributions of the merged jet invariant mass for muons with the estimates of the relevant backgrounds. The merged jet invariant mass is plotted after subtraction of all components except the diboson. The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 1-c:
Post-fit distributions of the merged jet invariant mass for muons with the estimates of the relevant backgrounds: subsequent normalized residual or pull distributions: (data $-$ fit)/(fit uncertainty). The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 1-d:
Post-fit distributions of the merged jet invariant mass for electrons with the estimates of the relevant backgrounds. The merged jet invariant mass is plotted for all events. The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 1-e:
Post-fit distributions of the merged jet invariant mass for electrons with the estimates of the relevant backgrounds. The merged jet invariant mass is plotted after subtraction of all components except the diboson. The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
png pdf |
Figure 1-f:
Post-fit distributions of the merged jet invariant mass for electrons with the estimates of the relevant backgrounds: subsequent normalized residual or pull distributions: (data $-$ fit)/(fit uncertainty). The error bars represent statistical uncertainties. The dashed vertical lines mark the signal region of 70 $ < m_{J} < $ 100 GeV, from which the the ${p_{\mathrm {T}}} $ distribution normalizations are extracted. |
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Figure 2:
$\mathrm{V}_\text {had}$ ${p_{\mathrm {T}}}$ distributions for the muon (left) and electron (right) channels after full selection and with the requirement 70 $ < m_{J} < $ 100 GeV. The MC errors are purely statistical. Examples of the effects of aTGCs are shown by the solid and dotted lines. Below we show the data/MC ratio. The last bin includes the overflow. |
png pdf |
Figure 2-a:
$\mathrm{V}_\text {had}$ ${p_{\mathrm {T}}}$ distributions for the muon channel after full selection and with the requirement 70 $ < m_{J} < $ 100 GeV. The MC errors are purely statistical. Examples of the effects of aTGCs are shown by the solid and dotted lines. Below we show the data/MC ratio. The last bin includes the overflow. |
png pdf |
Figure 2-b:
$\mathrm{V}_\text {had}$ ${p_{\mathrm {T}}}$ distributions for the electron channel after full selection and with the requirement 70 $ < m_{J} < $ 100 GeV. The MC errors are purely statistical. Examples of the effects of aTGCs are shown by the solid and dotted lines. Below we show the data/MC ratio. The last bin includes the overflow. |
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Figure 3:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for three pairwise combinations of the aTGC parameters in the LEP parametrization (top) and in the EFT formulation (bottom). The black dot represents the best fit point. |
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Figure 3-a:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($\lambda$, $\Delta{\kappa_\gamma}$) combination of aTGC parameters in the LEP parametrization. The black dot represents the best fit point. |
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Figure 3-b:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($\lambda$, $\Delta{g_1^{\mathrm{ Z }}}$) combination of aTGC parameters in the LEP parametrization. The black dot represents the best fit point. |
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Figure 3-c:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($\Delta{\kappa_\gamma}$, $\Delta{g_1^{\mathrm{ Z }}}$) combination of aTGC parameters in the LEP parametrization. The black dot represents the best fit point. |
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Figure 3-d:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($c_{\mathrm{ WWW }}/\Lambda^2$, $c_\mathrm{B}/\Lambda^2$) combination of aTGC parameters in the EFT formulation. The black dot represents the best fit point. |
png pdf |
Figure 3-e:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($c_{\mathrm{ WWW }}/\Lambda^2$, $c_{\mathrm{ W }}/\Lambda^2$) combination of aTGC parameters in the EFT formulation. The black dot represents the best fit point. |
png pdf |
Figure 3-f:
The 68 and 95% CL observed and expected exclusion contours in $\Delta \mathrm{NLL}$ are depicted for the ($c_{\mathrm{ W }}/\Lambda^2$, $c_\mathrm{B}/\Lambda^2$) combination of aTGC parameters in the EFT formulation. The black dot represents the best fit point. |
Tables | |
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Table 1:
Observed event yields and associated ratios (in parentheses) with respect to the pre-fit values extracted in the signal region (70 $ < m_J < $ 100 GeV). The term $\mathcal {A}\varepsilon $ (acceptance$\times $efficiency) includes W and Z branching fractions [37]. |
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Table 2:
Summary of expected and observed one-dimensional limits in the LEP parametrization. Each number pair represents the observed 95% confidence interval for that parameter. |
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Table 3:
Summary of one-dimensional limits in the EFT formulation for this analysis (*) compared to previous results. |
Summary |
In summary, our limits are consistent with the SM prediction and improve upon the sensitivity of the fully leptonic 8 TeV results [6,7] and the combined LEP experiments [37,42]. |
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Compact Muon Solenoid LHC, CERN |