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

Show full item record



Permalink

http://hdl.handle.net/10138/279392

Citation

The CMS Collaboration , Sirunyan , A M , Eerola , P , Kirschenmann , H , Pekkanen , J , Voutilainen , M , Havukainen , J , Heikkilä , J K , Järvinen , T , Karimäki , V , Kinnunen , R , Lampén , T , Lassila-Perini , K , Laurila , S , Lehti , S , Lindén , T , Luukka , P , Mäenpää , T , Siikonen , H , Tuominen , E , Tuominiemi , J & Tuuva , T 2018 , ' Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at root s=13 TeV ' , Physical Review Letters , vol. 121 , no. 22 , 221802 . https://doi.org/10.1103/PhysRevLett.121.221802

Title: Evidence for the Associated Production of a Single Top Quark and a Photon in Proton-Proton Collisions at root s=13 TeV
Author: The CMS collaboration; Sirunyan, A. M.; Eerola, P.; Kirschenmann, H.; Pekkanen, J.; Voutilainen, M.; Havukainen, J.; Heikkilä, J. K.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Tuuva, T.
Contributor organization: Department of Physics
Helsinki Institute of Physics
Date: 2018-11-29
Language: eng
Number of pages: 18
Belongs to series: Physical Review Letters
ISSN: 0031-9007
DOI: https://doi.org/10.1103/PhysRevLett.121.221802
URI: http://hdl.handle.net/10138/279392
Abstract: A search has been performed for heavy resonances decaying to ZZ or ZW in 2l2q final states, with two charged leptons (l = e, mu) produced by the decay of a Z boson, and two quarks produced by the decay of a W or Z boson. The analysis is sensitive to resonances with masses in the range from 400 to 4500 GeV. Two categories are defined based on the merged or resolved reconstruction of the hadronically decaying vector boson, optimized for high- and low-mass resonances, respectively. The search is based on data collected during 2016 by the CMS experiment at the LHC in proton-proton collisions with a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). No excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-1 and spin-2 resonances are derived as a function of the resonance mass, and exclusion limits on the production of W' bosons and bulk graviton particles are calculated in the framework of the heavy vector triplet model and warped extra dimensions, respectively.A search has been performed for heavy resonances decaying to ZZ or ZW in 2l2q final states, with two charged leptons (l = e, mu) produced by the decay of a Z boson, and two quarks produced by the decay of a W or Z boson. The analysis is sensitive to resonances with masses in the range from 400 to 4500 GeV. Two categories are defined based on the merged or resolved reconstruction of the hadronically decaying vector boson, optimized for high- and low-mass resonances, respectively. The search is based on data collected during 2016 by the CMS experiment at the LHC in proton-proton collisions with a center-of-mass energy of root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). No excess is observed in the data above the standard model background expectation. Upper limits on the production cross section of heavy, narrow spin-1 and spin-2 resonances are derived as a function of the resonance mass, and exclusion limits on the production of W' bosons and bulk graviton particles are calculated in the framework of the heavy vector triplet model and warped extra dimensions, respectively.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 root 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 (mu), a photon (gamma), an imbalance in transverse momentum from an undetected neutrino (nu), 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 backgroundonly 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 sigma(pp -> t gamma j) B (t -> mu nu b) = 115 +/- 17 (stat) +/- 30(syst) fb, which is consistent with the standard model prediction.
Subject: 114 Physical sciences
Z-GAMMA
COUPLINGS
Peer reviewed: Yes
Rights: cc_by
Usage restriction: openAccess
Self-archived version: publishedVersion


Files in this item

Total number of downloads: Loading...

Files Size Format View
PhysRevLett.121.221802.pdf 658.1Kb PDF View/Open

This item appears in the following Collection(s)

Show full item record