Production of W's with large transverse momentum at the CERN proton-antiproton collider

C Albajar ,G Jorat,S Tether,H Von Der Schmitt,B Van Eijk,L Gately,K Eggert,R Frey,M Demoulin,G Sajot,N Zaganidis,C Pigot,P Colas,C Markou,H Grassmann,K Bos,M Markytan,D Samyn,J Dorenbosch,G Ciapetti,E Tscheslog,D Linglin,V Vuillemin,P Petta,A Kernan,I Siotis,C Bacci,E Radermacher,P Kyberd,M Degiorgi,M Moricca,C Cochet,L Naumann,D Schinzel,J Garvey,G Salvini,P Erhard,D Pascoli,R Leuchs,S Centro,S Geer,I Zacharov,M Corden,C Zaccardelli,E Buckley,S Beingessner,G Pancheri,P Catz,H Faissner,C Perault,K Wacker,B Mours,L Zanello,W Jank,N Bains,G Piano Mortari,W Kienzle,M Della Negra,G Bauer,M Debeer,I Ten Have,I Sheer,E Eisenhandler,M Jimack,T Redelberger,A Gonidec,T Axon,C Rubbia,J Streets,E Pietarinen,W Von Schlippe,M.-N Minard,A Diciaccio,A Astbury,D Kryn,P Cennini,D Dau,G Busetto,A Wildish,A Placci,M Pimiä,J Sass,M Yvert,R J Homer ,C Tao ,P Sphicas ,F Szoncsó ,W.j Haynes ,J P Laugier ,L Dobrzyński ,N Ellis ,L Villaseñor ,K Sumorok ,G Arnison ,J.p Vialle ,W Rühm ,T R Wyatt ,S Wimpenny ,A Norton ,Y Giraud‐Héraud ,I F Fensome ,A Savoy-Navarro ,S Li ,P I P Kalmus ,Phil Flynn ,G Fontaine ,J P Porte ,H D Wahl ,A Nandi ,D Gee ,A Honma ,J Colás ,T C Bacon ,V Karimäki ,M Mohammadi ,Hans Hoffmann ,A Khan ,K Long ,J D Dowell ,R Sobie ,R Edgecock ,E Locci ,J P Mendiburu ,S J Haywood ,J Bellinger ,J Strauss ,W G Scott ,J P Debrion ,F Pauß ,H G Moser ,D G Charlton ,C.-E Wulz ,D Clarke ,T Virdee ,C Seez ,G Maurin ,J P Revol ,C Ghiglino ,R Kinnunen ,J Vrána ,M Ikeda ,A J Schwartz ,E Petrolo ,C Stubenrauch ,I R Kenyon ,P Nédélec ,P M Watkins ,A Bettini ,J A Coughlan ,J Tuominiemi ,A Givernaud ,Th Müller ,J Rohlf ,M Fincke-Keeler ,Paolo Rossi ,O C Allkofer ,A Taurok ,A Geiser ,R Keeler ,M Albrow ,C Ghesquière ,G Thompson ,B Aubert ,J R Batley ,F Ceradini ,A T Meneguzzo ,X Wu ,A Bézaguet ,T Markiewicz ,S Cittolin ,D Robinson ,G Cox ,D Denegri ,J.-P Merlo ,Isabelle Wingerter ,F Lacava ,M Krammer ,B Denby ,D Holthuizen ,T Shah ,T C Meyer ,D Smith ,J D Richman ,D Summers ,G Grayer ,Ph Ghez ,K Morgan ,W R Gibson ,D Cline ,J A Wilson ,H Reithler ,J P Lees ,E Duchovni ,S Levegrün ,J Kroll ,P Zotto

doi:10.1016/0370-2693(87)91257-3

Abstract

We have measured the W transverse momentum distribution ( p T W ) using a sample of 323 W → eν and W → μν events produced in proton-antiproton collisions at the CERN collider. In the present letter we extend the study of the distribution up to p T W ∼- m W and compare to leading and higher order QCD. This comparison is a precise test of QCD with hadron colliders and the inclusive spectrum gives good agreement over a large range of p T W . However we observed two events at very large p T W (∼- 100 GeV/ c) in which the W candidate recoils against an energetic di-jet system. Both events have a very large missing transverse energy and a jet-jet mass compatible with the W mass. In a separate analysis, a topologically similar event has been observed in which a high-mass di-jet system is balanced by a large missing transverse energy which could be interpreted as Z 0 → ν ν decay. We cannot easily explain these three events in terms of explicit second-order QCD calculations. However we cannot exclude at this stage the possibility that they are the result of non-gaussian fluctuations in the response of UA1 calorimetry or a statistical fluctuation in the data.

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