Measurement of the W +W −γ cross-section and first direct limits on anomalous electroweak quartic gauge couplings

G Abbiendi,T Kress,F Odorici,G Mikenberg,E Torrence,M Hauschild,D Waller,M Harin-Dirac,L Brigliadori,A De Roeck,M Hansroul,K Ackerstaff,K Runge,I Nakamura,P Gagnon,H Rick,R Perez-Ochoa,A Jawahery,A Frey,E Tsur,G Karapetian,H Voss,P Mendez-Lorenzo,D Axen,C Couyoumtzelis,M Boutemeur,O Sahr,G Giacomelli,M Kolrep,V Kartvelishvili,M Fierro,S Orito,M Donkers,P Kyberd,T Saeki,E Clay,G Duckeck,J Goldberg,D Lanske,P Scharff-Hansen,J Lauber,P Bock,K Sachs,I Cohen,D Chrisman,J Lillich,S Petzold,M Gruwé,J Grunhaus,B Poli,M Przybycień,M Jimack,K Roscoe,D Wetterling,P Taras,J Dubbert,A Biguzzi,P Hüntemeyer,R Liebisch,D Zer-Zion,C Littlewood,A Klier,T Behnke,A Okpara,P Mättig,J Von Krogh,M Sproston,J Polok,D Karlen,I Lawson,J Ludwig,P Vannerem,H Mes,A Michelini,A Macpherson,S Betts,W Mohr,S Braibant,K Stephens,O Schaile,A Fürtjes,J Patt,S Söldner-Rembold,K Stoll,V Zacek,J Böhme,H Landsman,W Gorn,M Thiergen,P Pfeifenschneider,M Hapke,F Wäckerle,R Van Kooten,T Kawamoto,D Glenzinski,J Couchman,A Fanfani,A W Lloyd ,David Charlton ,S Spagnolo,A Höcker ,K D Hoffman ,A Montanari,W G Scott ,H Jérémie ,B Dienes,P Bright-Thomas,S L Lloyd ,P I Kayal ,A Skuja,E K.g Sarkisyan ,C Schwick,F Fiedler,D Horváth,W M Sang ,J R Batley ,B List,C R Jones ,C M Hawkes ,T Mori,M J Oreglia ,F G Oakham ,I Bailey,T R Junk ,F K Loebinger ,J E Pilcher ,D.H Kim,G P Siroli ,R M Brown ,G N Patrick ,S Dallison,R J Teuscher ,C Ciocca,T E Marchant ,P G Estabrooks ,G Alexander,K Ishii,S F Ashby ,E Gross,P Capiluppi,A Macchiolo,H A Neal ,O Biebel,A Schöning,S A Robins ,S Bethke,N Rodning,J.R Carter,R L Coxe ,G Bella,D R Ward ,I P Duerdoth ,P Jovanović ,T R Wyatt ,S Tarem,J M Roney ,K W Bell ,A Rossi ,Ö Runólfsson ,M Fanti,P S Wells ,C Y Chang ,K Kawagoe,Robert Howard ,S Marcellini,A K Honma ,T Kühl ,E Etzion,P F Åkesson ,G Pásżtor ,M J Losty ,S Rosati,E Duchovni,P E.l Clarke ,K Graham,J S White ,P M Watkins ,Andrew J Martin ,S Schmitt,R G Kellogg ,C Hajdú ,J A Wilson ,R J Barlow ,R J Hawkings ,J A Mckenna ,N Wermes,R Seuster,N K Watson ,G Hanson ,G D Lafferty ,S Komamiya,E A Mckigney ,F S Merritt ,P Dervan,P Sherwood,J L Pinfold ,I J Bloodworth ,G Azuelos,R J Homer ,R J Hemingway ,C Grandi,Z L Trócsányi ,C K Hargrove ,C Rembser,H O Ogren ,K Desch,R Nisius,D R Rust ,D Bonacorsi,A M Smith ,G M Dallavalle ,B W Kennedy ,D I Futyan ,I Ueda,A D Schaile ,S W O’neale ,M Cuffiani,J Lu,T Mäshimo ,M Mannelli,I M Trigger ,J P Thomas ,J Letts,S Dado,Shinji Yamashita ,G Martı́nez ,J G Layter ,Takumi Kobayashi ,F Fabbri,K Harder,T Shears ,M Kobel,B Surrow,J Schieck,I Fleck,S D Talbot ,A.A Carter,A T Watson ,J W Gary ,J Kanzaki,Irmtraud M Meyer ,O C Cooke ,F R Jacob ,A Harel,D C Imrie ,P Igo‐Kemenes ,G Herten,J P Martin ,G A Snow ,B C Shen ,L Felď ,M S Dixit ,A Bellerive,J Allison,G W Wilson ,C P Ward ,P Ferrari,S Baumann,A H Ball ,J C Hill ,J R Pater ,K R Hossain ,J E Conboy ,D E Plane ,D Strom,G D Long ,Y Rozen,N Kanaya,A Quadt,F Meijers,K Nagai,R Ströhmer,C Geich-Gimbel,M Hildreth ,M Küpper ,R K Carnegie ,T P Kokott ,T Wengler,P Krieger,R Keeler ,D M Gingrich ,A Stahl,D Lellouch,R J Sobie ,M Schröder,W J Mcdonald ,S Arcelli,C Sbarra,D J Miller ,S Bentvelsen,C H Shepherd-Themistocleous ,T J Mcmahon ,S Mihara,M Schumacher,P R Hobson ,T Trefzger,R Davis,R Kowalewski ,H Burckhart ,S Asai,W F Mader ,S Towers,E Barberio,P Giacomelli,M A Thomson ,M F Turner-Watson ,R A Mcpherson ,G Gaycken,L Levinson,A A Faust ,R D Heuer ,K J Anderson ,M Verzocchi,O Boeriu

doi:10.1016/s0370-2693(99)01357-x

Abstract

A study of W +W − events accompanied by hard photon radiation produced in e +e − collisions at LEP is presented. Events consistent with two on-shell W-bosons and an isolated photon are selected from 183 pb −1 of data recorded at s =189 GeV. From these data, 17 W +W − γ candidates are selected with photon energy greater than 10 GeV, consistent with the Standard Model expectation. These events are used to measure the e +e −→W +W − γ cross-section within a set of geometric and kinematic cuts, σ ̂ WWγ =136±37±8 fb, where the first error is statistical and the second systematic. The photon energy spectrum is used to set the first direct, albeit weak, limits on possible anomalous contributions to the W +W − γγ and W +W − γZ 0 vertices: −0.070 GeV −2<a 0/Λ 2<0.070 GeV −2, −0.13 GeV −2<a c/Λ 2<0.19 GeV −2, −0.61 GeV −2<a n/Λ 2<0.57 GeV −2, where Λ represents the energy scale for new physics.

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