Evidence for exclusive gamma gamma -> W (+) W (-) production and constraints on anomalous quartic gauge couplings in pp collisions at and 8 TeV

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Khachatryan V., Sirunyan A. M., Tumasyan A., Adam W., Asilar E., Bergauer T., ...More

JOURNAL OF HIGH ENERGY PHYSICS, vol.2016, no.8, 2016 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 2016 Issue: 8
  • Publication Date: 2016
  • Doi Number: 10.1007/jhep08(2016)119
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Forward physics, Hadron-Hadron scattering (experiments), CROSS-SECTION, BOSON COUPLINGS, LIMITS, EVENTS
  • Istanbul University Affiliated: Yes


A search for exclusive or quasi-exclusive gamma gamma -> W (+) W (-) production, via pp -> p ((*)) W (+) W (-) p ((*)) -> p ((*)) mu (+/-)e(a") p ((*)) at 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)(mu (+/-)e(a")) > 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 3.4 sigma over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive gamma gamma -> 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.