Search for unstable heavy and excited leptons in e+e− collisions at ∝s = 170-172 GeV

K Ackerstaff,A A Carter,M S Dixit,C Beeston,J M Roney,R Bürgin,P M Watkins,J C Hill,C P Ward,J Goldberg,J Lauber,P G Estabrooks,C Markus,R Mir,M Fierro,E H Vokurka,E Lefebvre,B Wilkens,C R Jones,J E Conboy,C K Hargrove,P Bock,A M Smith,R K Carnegie,M F Turner-Watson,W G Scott,M Foucher,S Braibant,S A Robins,P Kyberd,T Geralis,M Jimack,A Macpherson,A S Turcot,T Behnke,V Kartvelishvili,A Michelini,T R Junk,A Skillman,S M Gascon-Shotkin,M Hauschild,O Schaile,L Brigliadori,A Biguzzi,G Giacomelli,G Duckeck,P Poffenberger,F K Loebinger,C Y Chang,M Jones,R J Barlow,A K Honma,M Boutemeur,F S Merritt,D Rigby,K R Hossain,J Grunhaus,R J Homer,F Odorici,M Hansroul,K Stoll,U Jost,W R Gibson,U Müller,J Patt,S Söldner-Rembold,M Kolrep,T Saeki,J E Bloomer,S Orito,W Mohr,L A Del Pozo,K Sachs,K Stephens,P Routenburg,A Sittler,S D Talbot,N K Watson,R M Brown,E A Mckigney,D R Rust,D Axen,I P Duerdoth,S Petzold,B C Shen,D Zer-Zion,P Pfeifenschneider,A Jawahery,P W Jeffreys,V Gibson,J E Pilcher,W P Lai,V Zacek,B Stockhausen,P Gagnon,J R Carter,N J Oldershaw,J Ludwig,C Hartmann,T Kawamoto,A T Watson,R W Springer,R J Hemingway,P Mättig,J Bechtluft,D Lazic,D E Hutchcroft,J W Gary,I J Bloodworth,F Scharf,G P Siroli,B W Kennedy,D G Fong,A Fürtjes,T P Kokott,A J Martin,A D Schaile,D M Gingrich,B Poli,A Joly,S R Lautenschlager,R Perez-Ochoa,G N Patrick,P Vikas,M Sproston,N I Geddes,D Chrisman,N Altekamp,H Voss,E Tsur,G M Dallavalle,M Thiergen,P Utzat,W J Mcdonald,P S Wells,H Mes,R Van Kooten,D E Plane,R D Heuer,G Yekutieli,F G Oakham,E Do Couto E Silva,J Pálinkás,P Taras,C Dallapiccola,A Posthaus,I Cohen,M Morii,M J Losty,K Runge,A M Rossi,A A Faust,J Gascon,C M Hawkes,M Hapke,R Bartoldus,D L Rees,D Lanske,A Rooke,J Steuerer,M Bobinski,M J Goodrick,M J Oreglia,P Hüntemeyer,D C Imrie,B Nellen,T Kress,P I Kayal,K W Bell,A Klier,D Karlen,S D Bird,J Von Krogh,H O Ogren,W Gorn,J G Layter,R G Kellogg,I Nakamura,O C Cooke,A Schüning ,D R Ward ,S J De Jong ,K J Anderson ,P Scharff-Hansen ,E Von Türne ,R J Hawkings ,J A Wilson ,S L Lloyd ,S Mihara ,P Schleper ,J Kirk ,J Meyer ,T Shears ,G D Long ,L J Levinson ,R Folman ,G Lafferty ,G A Snow ,M Schumacher ,A Macchiolo ,J Schieck ,Thomas J Mcmahon ,H M Fischer ,J P Martín ,C Grandi ,J R Batley ,P Krieger ,A N Bell ,P Giacomelli ,G Alexander ,D Horváth ,K Ishii ,N Wermes ,S Menke ,S J Hillier ,M Schröder ,D S Koetke ,G Wolf ,S Marcellini ,R Tafirout ,D Eatough ,Z L Trocsanyi ,C Hajdú ,S Bethke ,P E.l Clarke ,R Sobie ,H Neal ,J L Pinfold ,S Baumann ,D I Futyan ,S Robertson ,S W O’neale ,G Azuelos ,D Lellouch ,G Herten ,R Davis ,M Doucet ,C Sbarra ,Ch Geich-Gimbel ,H Evans ,I M Trigger ,S Arcelli ,D Glenzinskí ,S Asai ,T Mori ,S Kluth ,D Strom ,S Tarem ,E Barberio ,G Jones ,J S White ,J Allison ,M Hildreth ,E Duchovni ,Shinji Yamashita ,J Letts ,M Herndon ,E Ros ,S Schmitt ,Shun‐Ichi Tanaka ,T R Wyatt ,Ö Runólfsson ,Robert Howard ,M Cuffiani ,F Meijers ,M Mannelli ,Martin Ingram ,G Bella ,R A Mcpherson ,B Dienes ,N Rodning ,O Biebel ,P Jovanović ,A Oh ,S Dado ,Tatsuo Kobayashi ,S Komamiya ,A Skuja ,K Nagai ,R Ryłko ,M Gruwé ,B Schmitt ,S Bentvelsen ,P Igo‐Kemenes ,G W Wilson ,H Jérémie ,S Towers ,R Keeler ,A I Mincer ,A Wagner ,P R Hobson ,D G Charlton ,G Martı́nez ,A H Ball ,D J Miller ,A Montanari ,P A Hart ,H.‐C Schultz‐Coulon ,F Fabbri ,M Thomson ,P Schenk ,G Mikenberg ,R J Teuscher ,Uwe Rüppel ,J E.g Edwards ,G Hanson ,P Sherwood ,C D Burgard ,D Bonacorsi ,H Burckhart ,K Kawagoe ,T Mäshimo ,S Anderson ,Meirin Oan Evans ,I Fleck ,G Pásżtor ,A M Lee ,V Blobel ,K Desch ,B Bouwens ,M Kobel ,Y Rozen ,M Fanti ,P Szymański ,C Schwick ,C H Shepherd-Themistocleous ,E K.g Sarkisyan ,R Lahmann ,E Gross ,R Nisius ,J R Pater ,F Fiedler ,M Verzocchi ,P Capiluppi ,M J Pearce ,Roberto Giacomelli ,F Wückerle ,J A Mckenna

doi:10.1007/bf01245797

Abstract

We have searched for unstable neutral and charged heavy leptons, N and L±, and for excited states of neutral and charged leptons, ν* e*, μ* and τ*, in e+e− collisions at centre-of-mass energies of 170 and 172 GeV using the OPAL detector at LEP. No evidence for their existence was found. From the analysis of charged-current decays of pair-produced unstable heavy leptons, and of charged-current and photonic decays of pair-produced excited leptons, lower limits on their masses are derived. From the analysis of charged-current and photonic decays of singly-produced excited leptons, upper limits on the ratio of the coupling to the compositeness scale, ϕ/λ, are determined for masses up to the kinematic limit.

Full Text