Search for Associated Production of a Z Boson with a Single Top Quark and for tZ Flavour-Changing Interactions in Pp Collisions at √s = 8 TeV
Author(s)
CMS Collaboration; Abercrombie, Daniel Robert; Allen, Brandon Leigh; Apyan, Aram; Azzolini, Virginia; Barbieri, Riccardo; Baty, Austin Alan; Bi, Ran; Bierwagen, Katharina; Brandt, Stephanie Akemi; Busza, Wit; Cali, Ivan Amos; D'Alfonso, Mariarosaria; Demiragli, Zeynep; Di Matteo, Leonardo; Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Hsu, Dylan George; Iiyama, Yutaro; Innocenti, Gian Michele; Klute, Markus; Kovalskyi, Dmytro; Krajczar, Krisztian F.; Lai, Yue Shi; Lee, Yen-Jie; Levin, Amy Elizabeth; Luckey Jr, P David; Maier, Benedikt; Marini, Andrea Carlo; McGinn, Christopher Francis; Mironov, Camelia Maria; Narayanan, Siddharth Madhavan; Niu, Xinmei; Paus, Christoph M. E.; Roland, Christof E; Roland, Gunther M; Salfeld-Nebgen, Jakob Maxillian Henry; Stephans, George S. F.; Tatar, Kaya; Varma, Mukund Madhav; Velicanu, Dragos Alexandru; Veverka, Jan; Wang, Jing; Wang, Ta-Wei; Wyslouch, Boleslaw; Yang, Ming; ... Show more Show less
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A search for the production of a single top quark in association with a Z boson is presented, both to identify the expected standard model process and to search for flavour-changing neutral current interactions. The data sample corresponds to an integrated luminosity of 19.7 fb⁻1recorded by the CMS experiment at the LHC in proton-proton collisions at √s = 8 TeV. Final states with three leptons (electrons or muons) and at least one jet are investigated. An events yield compatible with tZq standard model production is observed, and the corresponding cross section is measured to be σ(pp → tZq → ℓνbℓ⁺ℓ⁻q) = 10₋₇⁺⁸fb with a significance of 2.4 standard deviations. No presence of flavour-changing neutral current production of tZq is observed. Exclusion limits at 95% confidence level on the branching fractions of a top quark decaying to a Z boson and an up or a charm quark are found to be ℬ(t → Zu) < 0.022% and ℬ(t → Zc) < 0.049%.[Figure not available: see fulltext.]. Keywords: Flavour Changing Neutral Currents; Hadron-Hadron scattering (experiments); Top physics
Date issued
2017-07Department
Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear ScienceJournal
Journal of High Energy Physics
Publisher
Springer Nature
Citation
Sirunyan, A. M. et al. “Search for Associated Production of a Z Boson with a Single Top Quark and for tZ Flavour-Changing Interactions in Pp Collisions at
√s = 8 TeV.” Journal of High Energy Physics 2017, 7 (July 2017): 3 © 2017 The Author(s)
Version: Final published version
ISSN
1029-8479