Evidence for electroweak production of W±W±jj in pp collisions at sqrt[s] = 8 TeV with the ATLAS detector.

G Aad,G Aielli,R Aben,H Abreu,M Pedersen,B Abbott,F Ould-Saada,A Strandlie,H Abramowicz,Z Czyczula,M Ugland,M Abolins,H Akerstedt,G Eigen,R Abreu,L Bugge,L Adamczyk,B Abi,M Agustoni,K Pajchel,C Alexa,B Stugu,O Abdinov,B Martin Dit Latour,H Sandaker,T Adye,A Lipniacka,S Abdel Khalek,S Stapnes,S Adomeit,T Buanes,L Smestad,D Cameron,E Gramstad,O Røhne,J Adelman,J Abdallah,A Kastanas,W Liebig,Ø Dale ,B K Gjelsten ,J A Aguilar-Saavedra ,P L Rosendahl ,Hass Abouzeid ,J R Catmore ,D L Adams ,S P Ahlen ,M K Bugge ,T Agatonović-Jovin ,T B Sjursen

doi:10.1103/physrevlett.113.141803

Abstract

This Letter presents the first study of W(±)W(±)jj, same-electric-charge diboson production in association with two jets, using 20.3 fb(-1) of proton-proton collision data at sqrt[s] = 8 TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two reconstructed same-charge leptons (e(±)e(±), e(±)μ(±), and μ(±)μ(±)) and two or more jets are analyzed. Production cross sections are measured in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. First evidence for W(±)W(±)jj production and electroweak-only W(±)W(±)jj production is observed with a significance of 4.5 and 3.6 standard deviations, respectively. The measured production cross sections are in agreement with standard model predictions. Limits at 95% confidence level are set on anomalous quartic gauge couplings.

Highlights

This Letter presents the with two jets, using 20.3 first fb−1 study of WÆWÆjj, same-electric-chparffigffi e diboson of proton-proton collision data at s 1⁄4 8 TeV production in association recorded by the ATLAS detector at the Large Hadron Collider
Production cross sections are measured in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms
The measured production cross sections are in agreement with standard model predictions

Summary

This Letter presents the first evidence for electroweak

WÆWÆjj production, where both W bosons decay leptonipcaffislffily1⁄4(8WTÆe→V lÆν, l 1⁄4 e, μ), using pp collision data at collected by the ATLAS detector at the LHC. SHERPA is used to produce WZ=γÃ þ jets events, taking into account both the strong and electroweak production mechanisms This sample is normalized to the next-toleading-order calculation in QCD from VBFNLO in each fiducial region [34,35], with an accuracy of 14% in the inclusive region and 11% in the VBS region. Contributions from SM processes that produce at least one nonprompt lepton from hadron decays in jets (W þ jets, tt, single top or multijet production, denoted by “other nonprompt background”) are estimated from data events that contain one lepton passing all selections and one nonisolated or loose-quality lepton These events, which are dominated by the nonprompt background, are scaled

Low mjj

The observed number of events is compared in

Findings

VBS region eÆμÆ