Evidence for exclusive γγ → W⁺ W⁻ production and constraints on anomalous quartic gauge couplings in pp collisions at √s = 7 and 8 TeV
Author(s)CMS Collaboration; Apyan, Aram; Barbieri, Richard Alexander; Baty, Austin Alan; Bi, Ran; Bierwagen, Katharina; Brandt, Stephanie Akemi; Busza, Wit; Cali, Ivan Amos; Demiragli, Zeynep; Di Matteo, Leonardo; Gomez-Ceballos, Guillelmo; Goncharov, Maxim; Gulhan, Doga Can; 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; 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.; Sumorok, Konstanty C; 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 exclusive or quasi-exclusive γγ → W⁺W⁻ production, via pp → p (*) W⁺W⁻p (*) → p (*) μ ± e ∓ p (*) at √s = 8 TeV, is reported using data corresponding to an integrated luminosity of 19.7 fb⁻¹. Events are selected by requiring the presence of an electron-muon pair with large transverse momentum p T (μ ± e ∓ ) > 30 GeV, and no associated charged particles detected from the same vertex. The 8 TeV results are combined with the previous 7 TeV results (obtained for 5.05 fb⁻¹ of data). In the signal region, 13 (2) events are observed over an expected background of 3.9 ± 0.6 (0.84 ± 0.15) events for 8 (7) TeV, resulting in a combined excess of 3.4σ over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive γγ → W⁺ W⁻ production. Upper limits on the anomalous quartic gauge coupling operators a 0,C W (dimension-6) and f M0,1,2,3 (dimension-8), the most stringent to date, are derived from the measured dilepton transverse momentum spectrum.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Laboratory for Nuclear Science
Journal of High Energy Physics
Khachatryan, V. et al. “Evidence for exclusive γγ → W⁺ W⁻ production and constraints on anomalous quartic gauge couplings in pp collisions at √s = 7 and 8 TeV.” Journal of High Energy Physics 2016, 8 (August 2016): 119 © 2016 The Author(s)
Final published version