Search for anomalous single top quark production in association with a photon in pp collisions at √s = 8 TeV

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Date
2016
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Abstract

The result of a search for flavor changing neutral currents (FCNC) through single top quark production in association with a photon is presented. The study is based on proton-proton collisions at a center-of-mass energy of 8 TeV using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb⁻¹. The search for tγ events where t → Wb and W → μν is conducted in final states with a muon, a photon, at least one hadronic jet with at most one being consistent with originating from a bottom quark, and missing transverse momentum. No evidence of single top quark production in association with a photon through a FCNC is observed. Upper limits at the 95% confidence level are set on the tuγ and tcγ anomalous couplings and translated into upper limits on the branching fraction of the FCNC top quark decays: ℬ(t → uγ) < 1.3 × 10(^{−4}) and ℬ(t → cγ) < 1.7 × 10(^{−3}). Upper limits are also set on the cross section of associated tγ production in a restricted phase-space region. These are the most stringent limits currently available.

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High Energy Physics - Experiment, Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Top physics
Citation
Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Asilar, E., Bergauer, T., Brandstetter, J., Brondolin, E., Dragicevic, M., Erö, J., Flechl, M., Friedl, M., Frühwirth, R., Ghete, V. M., Hartl, C., Hörmann, N., Hrubec, J., Jeitler, M., … Woods, N. (2016). Search for anomalous single top quark production in association with a photon in pp collisions at s = 8 $ \sqrt{s}=8 $ TeV. In Journal of High Energy Physics (Vol. 2016, Issue 4). Springer Science and Business Media LLC. https://doi.org/10.1007/jhep04(2016)035