Search for a high-mass dimuon resonance produced in association with b quark jets at $\sqrt{s}$ = 13 TeV

TL;DR

This paper reports the first dedicated LHC search for high-mass dimuon resonances produced with b quark jets, setting new constraints on Z' boson models with specific couplings and masses.

Contribution

It introduces a novel search for dimuon resonances with b jets at 13 TeV, providing the most stringent constraints to date on related Z' models.

Findings

Model-independent limits on signal events with b jets.

Excluded parameter space for Z' bosons with certain masses and couplings.

Constraints on Z' models consistent with low-energy b→sℓℓ measurements.

Abstract

A search for high-mass dimuon resonance production in association with one or more b quark jets is presented. The study uses proton-proton collision data collected with the CMS detector at the LHC corresponding to an integrated luminosity of 138 fb$^{-1}$ at a center-of-mass energy of 13 TeV. Model-independent limits are derived on the number of signal events with exactly one or more than one b quark jet. Results are also interpreted in a lepton-flavor-universal model with Z$'$ boson couplings to a bb quark pair ($g_\mathrm{b}$), an sb quark pair ($g_\mathrm{b}\delta_\mathrm{bs}$), and any same-flavor charged lepton ($g_\ell$) or neutrino pair ($g_\nu$), with $\left|g_{\nu}\right| = \left|g_\ell\right|$. For a Z$'$ boson with a mass $m_{\mathrm{Z}'}$ = 350 GeV (2 TeV) and $\left|\delta_\mathrm{bs}\right|$ $\lt$ 0.25, the majority of the parameter space with 0.0057 $\lt$ $\left|g_\ell\right|$ $\lt$ 0.35 (0.25 $\lt$ $\left|g_\ell\right|$ $\lt$ 0.43) and 0.0079 $\lt$ $\left|g_\mathrm{b}\right|$ $\lt$ 0.46 (0.34 $\lt$ $\left|g_\mathrm{b}\right|$ $\lt$ 0.57) is excluded at 95% confidence level. Finally, constraints are set on a Z$'$ model with parameters consistent with low-energy b $\to$ s$\ell\ell$ measurements. In this scenario, most of the allowed parameter space is excluded for a Z$'$ boson with 350 $\lt m_{\mathrm{Z}'}$ $\lt$ 500 GeV, while the constraints are less stringent for higher $m_{\mathrm{Z}'}$ hypotheses. This is the first dedicated search at the LHC for a high-mass dimuon resonance produced in association with multiple b quark jets, and the constraints obtained on models with this signature are the most stringent to date.