Evidence for Exclusive ?? {u2192} W+W{u2013} Production and Constraints on Anomalous Quartic Gauge Couplings in Pp Collisions at $$ \sqrt{s}
Author:
Publisher:
Published: 2016
Total Pages: 47
ISBN-13:
DOWNLOAD EBOOKA search for exclusive or quasi-exclusive ?? → W${̂+}$ W${̂–}$ production, via pp → p${̂(*)}$ W${̂+}$ W${̂–}$ p${̂(*)}$ → p${̂(*)}$ ?${̂±}$e${̂∓}$ 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$_{T}$(?${̂±}$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 3.4? over the background-only hypothesis. The observed yields and kinematic distributions are compatible with the standard model prediction for exclusive and quasi-exclusive ?? → W${̂+}$ W${̂–}$ production. Here, 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.
