The first evidence of events consistent with the production of a single top quark in association with a photon is reported. The analysis is based on proton-proton collisions at s=13 TeV and recorded by the CMS experiment in 2016, corresponding to an integrated luminosity of 35.9 fb-1. Events are selected by requiring the presence of a muon (μ), a photon (γ), an imbalance in transverse momentum from an undetected neutrino (ν), and at least two jets (j) of which exactly one is identified as associated with the hadronization of a b quark. A multivariate discriminant based on topological and kinematic event properties is employed to separate signal from background processes. An excess above the background-only hypothesis is observed, with a significance of 4.4 standard deviations. A fiducial cross section is measured for isolated photons with transverse momentum greater than 25 GeV in the central region of the detector. The measured product of the cross section and branching fraction is σ(pp→tγj)B(t→μνb)=115±17(stat)±30(syst) fb, which is consistent with the standard model prediction.

Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2018). Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at s =13 TeV. PHYSICAL REVIEW LETTERS, 121(22), 1-27 [10.1103/PhysRevLett.121.221802].

Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at s =13 TeV

Battilana, C.;Bonacorsi, D.;Braibant-Giacomelli, S.;Campanini, R.;Capiluppi, P.;Castro, A.;Cuffiani, M.;Fanfani, A.;FONTANESI, ELISA;Guiducci, L.;Iemmi, F.;Lo Meo, S.;Navarria, F. L.;Primavera, F.;Rovelli, T.;Siroli, G. P.;
2018

Abstract

The first evidence of events consistent with the production of a single top quark in association with a photon is reported. The analysis is based on proton-proton collisions at s=13 TeV and recorded by the CMS experiment in 2016, corresponding to an integrated luminosity of 35.9 fb-1. Events are selected by requiring the presence of a muon (μ), a photon (γ), an imbalance in transverse momentum from an undetected neutrino (ν), and at least two jets (j) of which exactly one is identified as associated with the hadronization of a b quark. A multivariate discriminant based on topological and kinematic event properties is employed to separate signal from background processes. An excess above the background-only hypothesis is observed, with a significance of 4.4 standard deviations. A fiducial cross section is measured for isolated photons with transverse momentum greater than 25 GeV in the central region of the detector. The measured product of the cross section and branching fraction is σ(pp→tγj)B(t→μνb)=115±17(stat)±30(syst) fb, which is consistent with the standard model prediction.
2018
Sirunyan, A., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., et al. (2018). Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at s =13 TeV. PHYSICAL REVIEW LETTERS, 121(22), 1-27 [10.1103/PhysRevLett.121.221802].
Sirunyan, A.M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.; Fle...espandi
File in questo prodotto:
Eventuali allegati, non sono esposti

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/672452
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? 0
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 13
social impact