CMS-PAS-FSQ-13-008

CMS-PAS-FSQ-13-008
Evidence for exclusive gamma-gamma to $\mathrm{W^+ W^-}$ production and constraints on Anomalous Quartic Gauge Couplings at $\sqrt{s} =$ 8 TeV
CMS Collaboration
June 2015

Abstract: A search for exclusive or quasi-exclusive $\gamma\gamma \rightarrow \mathrm{ W^{+}W^{-} }$ production, $\mathrm{pp \rightarrow p^{()} W^{+}W^{-} p^{()} \to p^{()} \mu^{\pm} e^{\mp} p^{()} }$ , at $\sqrt{s} =$ 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 $p_{\mathrm{T}}(\mu^{\pm} \mathrm{e}^{\mp})>$ 30 GeV and no associated charged particles detected from the same vertex. In the signal region 13 events are observed over an expected background of 3.5 $\pm$ 0.5 events, corresponding to an excess of 3.6 $\sigma$ over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the Standard Model prediction for exclusive and quasi-exclusive $\gamma\gamma \rightarrow \mathrm{ W^{+}W^{-} }$ production. The dilepton transverse momentum spectrum is studied for deviations from the Standard Model, and the resulting upper limits are compared to predictions assuming anomalous quartic gauge couplings.
Links: CDS record (PDF) ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; These preliminary results are superseded in this paper, JHEP 08 (2016) 119. The superseded preliminary plots can be found here.

CMS Publications