CMS-PAS-B2G-16-029

CMS-PAS-B2G-16-029
Search for heavy resonances decaying to pairs of vector bosons in the $\ell \nu q \bar{q}$ final state with the CMS detector in proton-proton collisions at $\sqrt{s} = $ 13 TeV
CMS Collaboration
December 2017

Abstract: A search for new heavy particles decaying to pairs of vector bosons is presented using data from the CMS detector corresponding to an integrated luminosity of 35.9 fb$^{-1}$ collected at a centre-of-mass energy of $\sqrt{s}= $ 13 TeV in 2016. One W boson is required to decay to e$\nu$ or $\mu\nu$, while the other boson is reconstructed as a single massive jet with substructure compatible with that of a highly-energetic $q \bar{q}^{(')}$ pair from a W or Z boson decay. The search is performed in the resonance mass range between 1.0 and 4.5 TeV. No significant deviations from the background only hypothesis are observed in the range of the search. The result is interpreted as an upper bound on the resonance production cross section. Comparing the excluded cross section values and the expectations from theoretical calculations in the spin-2 bulk graviton and heavy vector triplet models, WW resonances lighter than 1 TeV and WZ resonances lighter than about 3 TeV, respectively, are excluded at 95% confidence level.
Links: CDS record (PDF) ; inSPIRE record ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 05 (2018) 088. The superseded preliminary plots can be found here.

Figures	Summary	References	CMS Publications

Figures
png pdf	Figure 1: Feynman diagram for the production of a generic resonance decaying to the final state considered in this study.
png pdf	Figure 2: Jet soft-drop mass (left) and N-subjettiness ratio $ {\tau _{21}}$ (right) for data and simulated events in the top-enriched region in the electron channel. Data statistics only are shown as uncertainties.
png pdf	Figure 2-a: Jet soft-drop mass for data and simulated events in the top-enriched region in the electron channel. Data statistics only are shown as uncertainties.
png pdf	Figure 2-b: N-subjettiness ratio $ {\tau _{21}}$ for data and simulated events in the top-enriched region in the electron channel. Data statistics only are shown as uncertainties.
png pdf	Figure 3: Comparison between the fit result and muon (left) and electron (right) data distributions for $ {m_{\text {jet}}}$ (top) and $ {m_{\mathrm{W} {\mathrm {V}}}} $ (bottom) in the HP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 3-a: Comparison between the fit result and the muon data distribution for $ {m_{\text {jet}}}$ in the HP category. The background shape uncertainty is shown as a shaded band.
png pdf	Figure 3-b: Comparison between the fit result and the electron data distribution for $ {m_{\text {jet}}}$ in the HP category. The background shape uncertainty is shown as a shaded band.
png pdf	Figure 3-c: Comparison between the fit result and the muon data distribution for $ {m_{\mathrm{W} {\mathrm {V}}}} $ in the HP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 3-d: Comparison between the fit result and the electron data distribution for $ {m_{\mathrm{W} {\mathrm {V}}}} $ in the HP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 4: Comparison between the fit result and muon (left) and electron (right) data distributions for $ {m_{\text {jet}}}$ (top) and $ {m_{\mathrm{W} {\mathrm {V}}}} $ (bottom) in the LP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 4-a: Comparison between the fit result and the muon data distribution for $ {m_{\text {jet}}}$ in the LP category. The background shape uncertainty is shown as a shaded band.
png pdf	Figure 4-b: Comparison between the fit result and the electron data distribution for $ {m_{\text {jet}}}$ in the LP category. The background shape uncertainty is shown as a shaded band.
png pdf	Figure 4-c: Comparison between the fit result and the muon data distribution for $ {m_{\mathrm{W} {\mathrm {V}}}} $ in the LP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 4-d: Comparison between the fit result and the electron data distribution for $ {m_{\mathrm{W} {\mathrm {V}}}} $ in the LP category. The background shape uncertainty is shown as a shaded band. No events are observed with $ {m_{\mathrm{W} {\mathrm {V}}}} > $ 4.5 TeV.
png pdf	Figure 5: S/(S+B) event weighted distributions of the resonance mass for the bulk graviton $ \to \mathrm{W} \mathrm{W} $ signal (left) and $\mathrm{W'} \to \mathrm{W} \mathrm{Z} $ signal (right) for the 2D fit (top) and the $\alpha $ method (bottom). The signal is normalized to the production cross section of a graviton or W' of mass 2 TeV as predicted by the bulk graviton and HVT models, respectively, with parameters as defined in Sec. 3. The bottom panel shows the difference between weighted data and background events.
png pdf	Figure 5-a: S/(S+B) event weighted distribution of the resonance mass for the bulk graviton $ \to \mathrm{W} \mathrm{W} $ for the 2D fit. The signal is normalized to the production cross section of a graviton or W' of mass 2 TeV as predicted by the bulk graviton and HVT models, respectively, with parameters as defined in Sec. 3. The bottom panel shows the difference between weighted data and background events.
png pdf	Figure 5-b: S/(S+B) event weighted distribution of the resonance mass for the $\mathrm{W'} \to \mathrm{W} \mathrm{Z} $ signal for the 2D fit. The signal is normalized to the production cross section of a graviton or W' of mass 2 TeV as predicted by the bulk graviton and HVT models, respectively, with parameters as defined in Sec. 3. The bottom panel shows the difference between weighted data and background events.
png pdf	Figure 5-c: S/(S+B) event weighted distribution of the resonance mass for the bulk graviton $ \to \mathrm{W} \mathrm{W} $ for the $\alpha $ method. The signal is normalized to the production cross section of a graviton or W' of mass 2 TeV as predicted by the bulk graviton and HVT models, respectively, with parameters as defined in Sec. 3. The bottom panel shows the difference between weighted data and background events.
png pdf	Figure 5-d: S/(S+B) event weighted distribution of the resonance mass for the $\mathrm{W'} \to \mathrm{W} \mathrm{Z} $ signal for the $\alpha $ method. The signal is normalized to the production cross section of a graviton or W' of mass 2 TeV as predicted by the bulk graviton and HVT models, respectively, with parameters as defined in Sec. 3. The bottom panel shows the difference between weighted data and background events.
png pdf	Figure 6: Exclusion limits for a new resonance decaying to WW (left) and limits for a new resonance decaying to WZ (right) as a function of the resonance mass hypothesis.
png pdf	Figure 6-a: Exclusion limits for a new resonance decaying to WW as a function of the resonance mass hypothesis.
png pdf	Figure 6-b: Exclusion limits for a new resonance decaying to WZ as a function of the resonance mass hypothesis.

Summary

A search for new heavy resonances decaying to a pair of vector bosons is performed in events with one electron or muon and a massive jet. Using the N-subjettiness ratio ${\tau_{21}}$, massive jets are tagged as highly-energetic vector bosons (V = W, Z) decaying to quark pairs. The soft-drop mass is used as an estimate of the V-jet mass. The lepton momentum and missing energy are used to reconstruct the momentum of the $\mathrm{W} \to \ell \nu$ boson candidate, constraining the invariant mass of the $\ell \nu$ pair to the W boson mass value. A novel signal extraction technique is introduced based on a simultaneous fit of the V-jet mass and the diboson mass. The result is found to be consistent with the $\alpha$ method employed in previous versions of this analysis. No strong evidence of a new signal is found. The results are interpreted in terms of upper limits on the cross section for new resonances decaying to WW and WZ final states. Comparing the excluded cross section values and the expectation from theoretical calculations, WW resonances lighter than 1 TeV and WZ resonances lighter than about 3 TeV are excluded at 95% confidence level.

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