Search for Excited Quark Resonances in the Photon$$+$$Jet Invariant Mass Spectrum at 13 TeV

Abstract

We present a search for excited quarks (\(q^{*}\)) decaying into a photon and a hadronic jet in proton-proton collisions at \(\sqrt{s} = 13\,\)TeV with the CMS experiment. High transverse momentum photons and jets are selected to search for a resonance peak in the continuous invariant mass distribution of the photon\(+\)jet system. Excited quarks with mass (\({\mathrm M}_{q^{*}}\)) in the range, \(1.0< {\mathrm M}_{q^{*}} < 4.37\) TeV, are excluded for coupling multiplier \(f = 1.0\) at 95% confidence level. Results are also presented in terms of upper limits on cross section times branching ratio as a function of excited quark mass.