Combination of searches for heavy vector boson resonances in proton-proton collisions at $\sqrt{s}$ = 13 TeV

TL;DR

This work presents a comprehensive CMS analysis that combines 2016–2018 proton–proton collision data at $\

Abstract

A combined statistical analysis of searches for heavy vector boson resonances decaying into pairs of W, Z, or Higgs bosons, as well as into quark pairs ($\mathrm{q\bar{q}}$, $\mathrm{b\bar{b}}$, $\mathrm{t\bar{t}}$, $\mathrm{t\bar{b}}$) or lepton pairs ($\ell^+\ell^-$, $\ell\barν$), with $\ell =$ e, $μ$, $τ$, is presented. The results are based on proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$, collected by the CMS experiment from 2016 to 2018. No significant deviation from the expectations of the standard model is observed. The results are interpreted in the simplified heavy vector triplet (HVT) framework, setting 95% confidence level upper limits on the production cross sections and coupling strengths to standard model particles or the HVT bosons. The results exclude HVT resonances with masses below 5.5 TeV in a weakly coupled scenario, below 4.8 TeV in a strongly coupled scenario, and up to 2.0 TeV in the case of production via vector boson fusion. The combination provides the most stringent constraints to date on new phenomena predicted by the HVT model.

Figures (10)

• Figure 1: Representative Feynman diagrams for the production and decay of $\mathup{{{{ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ and $\mathup{{{{ \mathup{{{Z}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ bosons via the Drell--Yan process (upper row) and the VBF process (lower row). The $\mathup{{{{ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ ( $\mathup{{{{ \mathup{{{Z}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ ) boson decays to ${ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$ (${ \mathup{{{Z}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{H}}{} _{ {}} ^{ {}}} }\xspace$) (upper left, lower left), ${ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{Z}}{} _{ {}} ^{ {}}} }\xspace$ (${ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace{ \mathup{{{W}}{} _{ {}} ^{ {}}} }\xspace$) (upper middle, lower right), and fermion-antifermion pairs (upper right). The orange circle and the blue square indicate the fermionic and bosonic interaction vertices, respectively. The definition of the couplings is provided in Section \ref{['sec:signals']}.
• Figure 2: Expected and observed 95% $\text{CL}$ upper limits on the $\mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ boson production cross section as functions of the resonance mass $m_{{ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace}$ shown separately for the ${ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace\to\text{quarks}$ (upper) and ${ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace\to\text{leptons}$ (lower) categories. The limits are evaluated in the HVT model A scenario.
• Figure 3: Expected and observed 95% $\text{CL}$ upper limits on the $\mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ boson production cross section as functions of the resonance mass $m_{{ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace}$ shown separately for the ${ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace\to\text{bosons}$ category. The limits are evaluated under the HVT model B scenario.
• Figure 4: Expected and observed 95% $\text{CL}$ upper limits on the $\mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ boson production cross section as functions of the resonance mass $m_{{ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace}$ in the HVT models A (upper) and B (lower). The line corresponding to the ${ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace\to\text{bosons}$ category almost entirely overlaps with the combined result in the lower plot.
• Figure 5: Expected and observed 95% $\text{CL}$ upper limits on the $\mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}}$ boson production cross section as functions of the resonance mass $m_{{ \mathup{{{{ \mathup{{{V}}{} _{ {}} ^{ {}}} }\xspace}}{} _{ {}} ^{ {\prime}}} }\xspace}$ in the HVT model C.