Search for excited quarks in the gamma plus jet final state in proton-proton collisions at root s=8 TeV

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A search for excited quarks decaying into the (\gamma)+jet final state is presented. The analysis is based on data corresponding to an integrated luminosity of 19.7 fb⁻¹ collected by the CMS experiment in proton-proton collisions at (\sqrt{s}) = 8 TeV at the LHC. Events with photons and jets with high transverse momenta are selected and the (\gamma)+jet invariant mass distribution is studied to search for a resonance peak. The 95% confidence level upper limits on the product of cross section and branching fraction are evaluated as a function of the excited quark mass. Limits on excited quarks are presented as a function of their mass and coupling strength; masses below 3.5 TeV are excluded at 95% confidence level for unit couplings to their standard model partners.

CMS, Physics, Photon, Jet, PARTON DISTRIBUTIONS, Astronomy & Astrophysics, Physics, Nuclear, Physics, Particles & Fields
Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., Erö, J., Fabjan, C., Friedl, M., Frühwirth, R., Ghete, V. M., Hartl, C., Hörmann, N., Hrubec, J., Jeitler, M., Kiesenhofer, W., Knünz, V., Krammer, M., Krätschmer, I., … Woods, N. (2014). Search for excited quarks in theγ+jetfinal state in proton–proton collisions ats=8 TeV. In Physics Letters B (Vol. 738, pp. 274–293). Elsevier BV.