UvA-DARE is a service provided by the library of the University of Amsterdam (https://dare.uva.nl)

UvA-DARE (Digital Academic Repository)

Observation of orbitally excited B mesons

Abreu, P.; et al., [Unknown]; Agasi, E.; Augustinus, A.; Haider, S.; Hao, W.; Holthuizen, D.J.;Kluit, P.; Koene, B.K.S.; Ruckstuhl, W.; Siccama, I.; Timmermans, J.; Toet, D.Z.; vanApeldoorn, G.W.; van Dam, P.H.A.; van Eldik, J.E.DOI10.1016/0370-2693(94)01696-APublication date1995

Published inPhysics Letters B

Link to publication

Citation for published version (APA):Abreu, P., et al., U., Agasi, E., Augustinus, A., Haider, S., Hao, W., Holthuizen, D. J., Kluit, P.,Koene, B. K. S., Ruckstuhl, W., Siccama, I., Timmermans, J., Toet, D. Z., van Apeldoorn, G.W., van Dam, P. H. A., & van Eldik, J. E. (1995). Observation of orbitally excited B mesons.Physics Letters B, 345(4), 598-608. https://doi.org/10.1016/0370-2693(94)01696-A

General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s)and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an opencontent license (like Creative Commons).

Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, pleaselet the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the materialinaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letterto: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. Youwill be contacted as soon as possible.

Download date:01 Apr 2021

https://doi.org/10.1016/0370-2693(94)01696-Ahttps://dare.uva.nl/personal/pure/en/publications/observation-of-orbitally-excited-b-mesons(6c230810-a50f-4bfd-bea0-44c727423550).htmlhttps://doi.org/10.1016/0370-2693(94)01696-A

23 February 19%

PHYSICS LETTERS B

I-..ShVIt~I< Physics Letters B 345 ( 1995 ) 598-608

Observation of orbitally excited B mesons DELPHI Collaboration

P. Abreu “, W. Adam h, T. Adye a(, E. Agasi =, I. Ajinenko ‘q, R. Aleksan ‘“, G.D. Alekseev O, P.P. Allport “, S. Almehed ‘, F.M.L. Almeida’“, S.J. Alvsvaag d, U. Amaldi h, S. Amato ‘“, A. Andreazza ab, M.L. Andrieux “’ , l? Antilogus Y, W-D. Ape1 P, Y. Amoudm, B. &man ;I’,

J-E. Augustin ‘, A. Augustinus ae, P. Baillon h, P. Bambade ‘, F. Barao “, R. Barate m, G. Barbiellini ‘“, D.Y. Bardin O, G.J. Barker pi, A. Baroncelli ‘O, 0. Barring h, J.A. Barrio ‘,

W. Bartl Bz, M.J. Bates rt’, M. Battaglia “, M. Baubillier”, J. Baudot m, K-H. Becks bb, M. Begalli ak, P. Beilliere g, Yu. Belokopytov h, P. Beltranj, A.C. Benvenuti e, M. Berggren”p,

D. Bertrand b, F. Bianchi at, M. Bigi ‘I, M.S. Bilenky O, P. Billoir w, J. Bjarne ‘, D. Bloch i, M. Blume bb, S. Blyth ai, V. Bocci 3m, T. Bolognese ‘“, M. Bonesini ‘b, W. Bonivento Bb, P.S.L. Booth”, G. Borisov”q, C. Bosio”, B. Bostjancic a, S. Bosworthai, 0. BotneraW,

B. Bouquets, C. Bourdarios”, T.J.V. Bowcock “, M. Bozzo I, l? Branchini ao, K.D. Branda, R.A. Brenner “, H. Briand w, C. Bricman b, L. Brillault w, R.C.A. Brown h, P. Bruckmanq,

J-M. Brunetg, L. Bugge ‘g, T. Buran ag, A. Buys h, M. Caccia *, M. Calvi ab, A.J. Camacho Rozas pP, T. Camporesi h, V. Canale am, M. Canepa e, K. Cankocak =, F. Cao b,

F. Carena h, P. Carrilho “‘, L. Carroll “, C. Caso ‘, V. Cassic a’, M.V. Castillo Gimenez ‘Y, A. Cattai h, F.R. Cavalloe, L. Cerrito an’, V. Chabaud h, A. Chan ‘, Ph. Charpentier h,

L. Chaussard Y, J. Chauveau w, P. Checchia ‘j, G.A. Chelkov O, P. Chliapnikov 4, P. Chochula f, V. Chorowicz h, J.T.M. Chrin ‘Y, V. Cindro nr, P. Co!lins h, J.L. Contreras s, R. Contri [, E. Cortina”Y, G. Cosme ‘, F. Cossutti ‘“, H.B. Crawley ‘, D. Crennell &, G. Crosetti ‘,

J. Cuevas Maestro ah, S. Czellar “, E. Dahl-Jensen ac, J. Dahm bb, B. Dalmagne ‘, M. Dam”g, G. Damgaard”“, A. Daum P, PD. Dauncey ae, M. Davenport h, W. Da Silva”, C. Defoix g,

G. Della Ricca”“, P. Delpierrem, N. Demaria”‘, A. De Angelis h, H. De Boeck b, W. De Boer P, S. De Brabandere b, C. De Clercq b, M.D.M. De Fez Laso aY, C. De La Vaissiere w,

B. De Lotto’“, A. De Minab, L. De Paulaa”, C. De Saint-Jeanan, H. Dijkstra h, L. Di Ciaccio am, F. Djama’, J. Dolbeau g, M. Donszelmann h, K. Doroba ba, M. Dracos i, J. Drees bb,

K.-A. Drees bb, M. Dris af, Y. Dufour g, F. DuPont m, D. Edsall I, R. Ehret P, T. Ekelof aw, G. Ekspong “, M. Elsing bb, J-P. Engel i, N. Ershaidat w, M. Espirito Santo “, D. Fassouliotis “‘, M. Feindt h, A. Fenyuk ‘q, A. Ferrer pY, T.A. Filippas af, A. Firestone a, H. Foeth h, E. Fokitis af,

F. Fontanelli ‘, F. Formenti h, J-L. Fousset a, B. Franekae, P. Frenkiel g, D.C. Fries P, A.G. Frodesend, R. Fruhwirthnz! F. Fnlda-QuenzerS, H. Furstenau h, J. Fuster h, D. Gambaa’,

0370-2693/95/W9.50 @ 1995 Elsevier Science B.V. All rights mervcd SSDIO370-2693(94)01696-E

DELPHI Collnborarica iPhysics Ler~rs B 345 (1995) 59G608 s!x’

M. Gandelman r, C. Garcia ‘y, J. Garcia ‘r, C. Gaspar h, U. Gasparini 4, Ph. Gavillet h, E.N. Gazis 3f, D. Gele i, J-P Gerber i, D. Gillespie h, R. Gokieli ba, B. Golob ar,

J.J. Gomez Y Cadenas h, G. Gopal “, L. Gorn D, M. Gorski ba, V. Gracco (, F. Grard b, E. Graziani 8o, G. Grosdidiers, P. Gunnarsson RS, J. Guy aC, U. Haedingerp, F. Hahn hb,

M. Hahn p, S. Hahn bb, S. Haider ae, Z. Hajduk”, A. Hakansson %, A. Hallgren aw, K. Hamacher bb, W. Hao ae, F.J. Harris ai; V. Hedberg x, R. Henriques “, J.J. Hernandez ay,

J.A. Hernando ‘y, I? Herquet b, H. Herr h, T.L. Hessing h, E. Higon ay, H.J. Hilke h, T.S. Hill p, S-O. Holmgren as, P.J. Halt”‘, D. Holthuizenx, P.F. Honores, M. Houlden”, J. Hrubec pz,

K. Huet b, K. Hultqvist “, l? Ioannou ‘, J-N. Jackson “, R. Jacobsson ;Is, P. Jalochaq, R. Janik f, G. Jarlskog x, P. Jarry an, B. Jean-Marie ‘, E.K. Johansson a, L. Jcnsson ‘, P Juillot i,

M. Kaiser P, G. Kalmus b, F. Kapusta w, M. Karlsson “, E. Karvelas j, S. Katsanevas ‘, E.C. Katsoufis af, R. Keranen “, B.A. Kbomenko”, N.N. Khovanski O, B. King “, N.J. Kjaer ac,

H. Klein h, A. Klovning d, P. Kluit =, J.H. Koehne p, B. Koeneae, P. Kokkiniasj, M. Koratzinos h, V. Kostioukhine ‘q, C. Kourkoumelis c, 0. Kouznetsov “, P-H. Kramer bb,

M. KrammeraL, C. Kreuterp, J. Krolikowski bn, I. Kronkvist x, Z. KrumsteinO, W. Krupinskiq, P. Kuhinec f, W. Kucewiczq, K. Kulkaaw, K. Kurvinen “, C. Lacasta aY. I. Laktineh Y,

C. Lambropoulos j, J.W. Lamsa ‘, L. Lanceri ‘“, D.W. Lane ‘, P. Langefeld bb, V. Lapin q, I. Last “, J-P. Laugier ‘“, R. Lauhakangas “, G. Leder az, F. Ledroit m, V. Lefebure b,

C.K. Legan 3, R. Leitner od, Y. Lemoigne an, J. Lemonne b, G. Lenzen bb, V. Lepeltier ‘, T. Lesiak 4, R. Lindner bb, A. Lipniacka ‘, l.. Lippi 4, B. Loerstad ‘, M. Lokajicek k,

J.G. Loken ni, A. Lopez-Fernandez h, M.A. Lopez Aguera”p, D. Loukas j, J.J. Lozano ay, P. Lutz an , L. Lyons ai, G. Maehlum P, J. Maillardg, A. Maio “, A. Maltezosj, V. Malychev O,

F. Mandl 3z, J. Marco ap, B. Marechal ‘“, M. Margoni d, J-C. Marin h, C. Mariotti ‘O, A. Markouj, T. Maron bb, C. Martinez-Rivero”p, F. Martinez-Vidal’y, S. Marti i Garcia”)‘,

F. Matorras”P, C. Matteuzxi Ib, G. Matthiae am, M. Mazzucato 4, M. MC Cubbin h, R. MC Kay ‘, R. MC Nulty “, J. Medbo aw, C. Meroni ab, W.T. Meyer a, M. MichelottoJ, E. Migliore “, I. Mikulec =, L. Mirabito Y, W.A. Mitaroff Oz, U. Mjoemmark ‘, T. Moa a, R. Moeller “,

K. Moenig h, M.R. Monge ‘, P. Morettini ‘, H. Mueller P, W.J. Murray ae, B. Murynq, G. Myatt ai, F. Naraghi “‘, EL. Navarriae, S. Navas aY, P. Negri ab, S. Nemecek k,

W. Neumann bb, N. Neumeister ilz, R. Nicolaidou c, B.S. Nielsen “, V. Nikolaenko Y, P. Niss “, A. Nomerotski 4, A. Normand”‘, W. Oberschulte-BeckmannP, V. Obraztsov 04,

A.G. Olshevski O, R. Orava”, K. Osterberg”, A. Ouraou”“, P Paganini ‘, M. Paganoni ab, P. Pages i, R. Pain w, H. Palkaq, Th.D. Papadopoulou”‘, L. Pape h. F. Parodi ‘, A. Passeri ‘O,

M. Pegoraro 4, J. Pennanen “, L. Peralta “, V. Perevozchikov w, H. Pernegger az, M. Pernicka m, A. Perrottae, C. Petridou au, A. Petrolini ‘, H.T. Phillips a!, G. Piaria!, F. Pierrem, M. Pimenta”,

S. Plaszczynski ‘, 0. Podobrinp, M.E. Pol r, G. Polokq, P. Poropat”“, V. Pozdniakov’, M. Prest au, P. Priviteraam, A. Pullia ab, D. Radojicic ai, S. Ragazzi ab, H. Rahmani af, J. Rames k, P.N. Ratoff t, A.L. Read as, M. Reale bb, P. Rebecchi s, N.G. Redaelli ab, M. Regler =, D. Reid h,

PB. Renton pi. L.K. Resvanis c, F. Richard s, J. Richardson “, J. Ridky 6, G. Rinaudoa, I. Ripp a1’, A. Romero pt, I. Roncagliolo p, P. Ronchese 4, V. Ronjin q, L. Roos m,

600 DELPHI Collubomtion /Physics Lerrers B 345 (I 995) 598-608

E.I. Rosenberg 3, E. Rosso h, P. Roudeau s, T. Rovelli rr W. Ruckstuhl ‘e, V. Ruhlmann-Kleider3”, A. Ruiz IP, K. Rybickiq, H. Saarikko”, Y. Sacquin”“, A. Sadovsky ‘,

G. Sajot m, J. Salt 3Y, J. Sanchez z, M. Sannino’, H. Schneider f’, M.A.E. Schyns bb, G. Sciolla3’, F. Scuri O”, Y. Sedykh O, A.M. Segar ai, .12. Seitz P, R. Sektlin “, R.C. Shellardak, I. Siccama ae,

l? Siegrist an, S. Simonctti In, F. Simonetto3j, AN. Sisakian O, B. Sitar f, T.B. Skaali”“, G. Smadjay, N. Smirnov , nq 0. Smirnova”, G.R. Smith ‘(, R. Sosnowski bn, D. Souza-Santos 3k, T. Spassov “, E. Spiriti ““, S. Squarcia “, H. Staeck bb, C. Stanescu ‘O, S. Stapnes ‘g, I. Stavitski ‘j,

G. Stavropoulosj, K. Ctepaniak , . ba F Stichelbaut h, A. Stocchi ‘, J. Strauss “, R. Strub i, B. Stugu d, ?.I. Szczekowski , ba M. Szeptycka ba, T. Tabarelli ab, 0. Tchikilev 39,

G.E. Theodosiou j, A. Tilquin aa, J. Timmermans pe, L.G. Tkatchev O, T. Todorov i, D.Z. Toet ‘e, A. Tomaradze b, B. Tome I!, L. Tortora ‘“, G. Transtromer ‘, D. Treille h, W. Trischuk h, G. Tristram 1, A. Trombini ‘, C. Troncon Ib, A. Tsirou h, M-L. Turluer an, T. Tuuva “, J.A. Tyapkin”, M. Tyndel “, S. Tzamarias “, B. Ueberschaer bb, S. Ueberschaer bb,

0. IJllaland h, V. Uvarovr ;‘q, G. Valenti ‘, E. Vallazza h, J.A. Valls Ferrer3Y, C. Vander Velde b, G.W. Van Apeldoorn”, P. Van Darnac”, W.K. Van Doninckb, J. Van Eldik*, G. Vegni ab, L. Ventura “j, W. Venus *‘,, F. Verbeure b, M. Verlato3j, L.S. Vertogradov O, D. Vilanova”“,

P. Vincent Y, L. Vitale ‘“, E. Vlasov ‘q, A.S. Vodopyanov’, M. Voutilainen”, V. Vrba k, H Wahlen bb, C. Walck Bs, A. Wehrbb, M. Weierstall bb, P. Weilhammer h, A.M. Wetherell h,

D. Wicke bb, J H Wickens b, M. Wielers P, G.R. Wilkinson”‘, W.S.C. Williams”‘, M. Winter i, . . M. Witek h, G. Wormser s, K. Woschnagg Bw, K. Yip”‘, L. Yu li, 0. Yushchenko ‘q, F. Zach Y, A. Zaitsev ‘Iq, . A Zalewskaq. P. Zalewski b’, D. Zavrtanik 3r, E. Zevgolatakosj, N.I. Zimin O,

M. Zito pn, D. Zontar “, K. Zuberi ;ri, G.C. Zucchelli “, G. Zumerle ‘j J AIIW Lctborcr~~~r~ twd Deptrrmient o$ Phpics, Iowa Stule Univer.si/y Ames IA 501 I. USA

h Phy.rics /~cpc:rnrvr~r. Univ. /nsrel/inq Anrwerpen, Universitcir.~pleirl I. B-2610 Wilrijk. Bd~i~tm cold IIHE. ULB-VUB. Pleinlmn 2. B-1050 Bnrssels. Belgium

rrrrti Fucrtlfe des Sciences, Univ. de I’Emr Mans. Av. Muistriuu 19. LI-7GGO Mans, Belgium c Plrysic~s /tib~nu!or): Universby of Arhens, Solonos S/r. IOJ. CR-IWXG A:hens. Greece J Deptrrmren/ of Physics. Uni,~er.sity of Bergen. Allepten SS, N-5007 Bergen. Nonvuy

F DiJmrrimento d; fi;i’siw Universi/ti di Bolopm und INFN, Viu Irnerio 46, J-40126 Eol~~~no. Im!, I’ Comenius Universify, Fi~cuby of Mothemun’c.s and Physics, Mlynsku Dolina. SK-84215 &uri.~luvu. Slovak ReJmblic

E Collt$e de Frunce, Llh. de Physique Corpusculoire. IN2P3-CNRS. F-75231 Puris Cedex 05. Frunce ’ CERN, CH-121 I Cenevu 23, Swbzerland

i Cerrtre de Recherche Nncleuire. lN2P3 - CNRSrULP - BP20, F-67037 Strasbourg Cedex. France

’ Ins!imte of Nuclear Ph,wics. N.C.S.R. Demokrilos. P.0. Box 60228, CR-I5310 Adrens. Greece ’ FZlJ, Ins/. c$ Physics oJ /he C.A.S. High Energy Phy.~ics Division, Na Sloronce 2, I80 JO. Pruhu 8, Czech Republic

’ Diportimrnto c/i Fisicu. Uuiversirti di Genovu und INFN, Viu Dodecuneso 33, l-16146 C;enovu. Ih11y m hr~lilw des Sciences Nucleoires, IN2P3-Ch’RS, Universite de Grenoble I. F-38026 Grenoble Cedtx. Frunce

’ Resenrch Instimre for Hixlt Energy Phpics, SEFI F?O. Box 9. FIN-o0014 Helrinki, Finlund ” Joint Insrimk for Nuclear Reseurs~k. D~tbnu. HelId Posf Ogice. P.0. Box 79. 101 OGG Moscow, Russiun Federurion

P Insrilrrt ftir Evperimenrelle Kernpllysik. Universirih Korlsruhe. Posyi~ch 6980, D-76128 Kurbruhe. Germuny q Hi,s$ Energy Phy~sics I&oruror~: Insrirtrre of Nucleur Phy.rics. UI. Kuwiory 26u. PL .3005.5 Kmkow 3G. fitlund

r Cenm) Brusilciro de Pr.si/uistra Fishus. rncc Xcrrier Sikuud ISO. 811-22290 Rio de Juneiro. Brazil ’ Univercifc’ de At:is-Sod. ilrb. de I’Ac~ce’ldrurenr Lineuire. IN2P3CNRS. Bar 200, F-91405 Orsuy Cede.& Frunce

’ School of Phy.rics cord Moteriu1.s. Universiry rfl Luncuste,: Luncusrer LA1 4Yl3. UK ’ Lll? 1.57; FCUL - Av. Elius Curcia. IJ-l(o). P-loo0 Lisbou Codex, PnrmSal

’ Depuronenr of Phy.sics. Universiry of Liverpool, t?O. Box 147, Liverpool L69 3/3X, UK w LPNHE. lN2P3CNRS. Universirfs Puris VI et VII. Rmr 33 (RdC). 4 pluce Jossieu. F-75252 p0ri.s Cede,x 05. Frunce

’ DepurUfrer~f 0s Phyi% L’uiwr.cify of Luud. Siilw~ufun IJ, S-22363 Lund. Sweden ? iJrriversi!J Clmd~ Bernard de Lyw. IPNL. I.V2P3-CNRS. F-69622 Wkrtrbunnc Cede.\; France

’ Uniwr~idad Confp/rrftvf,sf. .4f’dfr. G7rnphffense s/n. E-2RWO Mudrid, Spcriu A’ Unix d’Air _ Mrrseilk !I _ CPP. INZP3-CNRS. F-13288 Murseillc Ccdex 09. Frunce

ah Diptrrtiwrnto ,li Fisicu. Uu:w!:vi/ti di .Uilurro curd INFN, \/ire Cehricc 16. I-20133 Milm. Iftr!\ x Nit/s Rnhr hli/rtre. fd~~,~dtrrmvej Ii. DK-2100 Coperrho~en 0. Denmurk

ad NC hitcletrr Ctw;rc I/’ AIFK Clrtrrks IJ~kwi!,: Areul MFE 1’ Holesovkkuc~h 2. 180 00. Pruhu 8. Cztvh Republic 15 NIKHEF-Ii. Postbrts 4lRRZ. NL -1009 DB Am~rerdum The Nerherland~t

il ’ N~V;rriorrctl lkhnit trl Uuiver.si?\: Ph\:Gc.s Depur1mmI. Zfqrflfh C~II~~US. CR- 15773 Athem G~ecc’e :‘E Physics Depurfmnr, &iver,si/y of Oslo. Blindenr. N-1000 Oslo 3, Nunwp

ah &,o. Fisicu. Uuir: Oviedo. C/f! P&e: Ca.m. SIN-33006 Oviedo, Sptrin i l i D~~p~07wnf o,c Physics. fhiwrsiry of o.ifim~, Keble Road, O.\-fvd OXf 3RH. UK

:li Dipur/irrrcrtru di Fisku. Universifci rli Padmu uud INFN. Viu Munolo 8. I-35111 i’mh. h/v xk Depro. de Fi.riirr. f’mr[‘citr Univ. Ck/~i/icu. C.P 3807/ RI-22453 Rio de koreim, Bmzil

p’ Ru~he~;@d Applerou Lcrhnruror?: Chilrou. Didcur OX11 O@X. UK m Diptrr/iswnro di Fisiw Uuitwsiftti t/i Rornu Ii crml INFN, Tar krgutu. I-00173 ROIIIC. Ittr!,’

il” Ctwrre d’Mrr& tic 5irdc1y DS.M/DAPNIA. F-91 I91 G~sur- Yvette C&.x. Frunce =I’ Isrinrto Superiore di SunitO. I.v. Nuz. t/i Fisica N~tcl. (INFN). Viale Regivu E/em 299, l-0016/ Hcmr. hly

w C. E.A.Fhl., C.S. I. C. _ Unir: Cunrubriu, Avdcr. 10s Casrros. (CICYT-AEN93-0832). S/N-39006 Sunmnde): Spain ;rl IIISI. $)r High Euer,qy Phykx. Serprrkm PO. Bus 35. Pro/vim. (Moscow Relpion). Russiun Federariwt

I’ .I. S/efitrl hrsrintre crud Deput?ureur o/ Physics. Universitv uf Ljubljcura, JUIIWW 39, SI-61000 Ljuhljcma. Shwenitr as Fy.sikunr. S~~kl;ol,rr Umverri!\: Bo.; 6730. S-l I3 M Srockhohrr. Sweden

II’ Dipurtinwnro di Firicu Spcrinw~tale. llnivtwirci di ‘hino and INFN. Viu P. Giuriu I. I-10125 Titrin, Iltrl> au DipartimenIo di Fisictr. Uniwrsirir di Triexfe and INFN, \‘icc A. Vuleri;) 2. I-34127 Triesfe. Ihtr!\

curd /.v/i/um di Fisiw. Unive,rifti di Udine. /-33/00 Udine. I/cI!\~ J’: Unit:. Federul do Rio (11: Junriro. C.P 6R.T-78 Cidude Unix:. llhu du Fumlcio BR-21945-970 Rio de Jurreim, Brazil

:I”’ Depurtnrerr! u/ Radiurion Sciences. Universiry of Upp.rtrka. P 0. Box 533. S-751 21 Uppsula. Sweden

ly IFIC. Vulencia-CSIC, and D.FA.M.N.. U. de Vulenciu. Avdu. Dr. Moliner SO. E~J6100 Burjussor (Vulenck~). Spuin ill lnsrirut fiir Iioclre~~er~ir~~h,:Fik. &err. Akud. d HBsensrlr.. Nikolsdntfiv~u.w 18. A-1050 Vienna. An&cc

hJ Insr. Nucleus: S~r&a urrcl Uni\~cr.fi/,~ c.;’ I\‘trrsuw UI. Ho;u 6Y. PL-006RI \Yurscrw Puhmd M, Fuchbcrcich Ph~,~iL. Univwsi/v of Wrp;~c~;crl. fo.~~/ix!l 100 127. D-42097 Wtrpperful I, Gernrtrrr.b .

Received 20 December 1994 Ediw: 1,. Mmtanrl

Abstract

Experimental evidcncc for the cxistcnce ol‘ orhitally excited R meson states is presented in an analysis of the &r and B*T distribution of Q = I~I( 3**) - rn[ II ’ l ’ ) - 111(n) using %‘I decay dara taken with the DELPHI detector at LEP

The mean Q-vaiuc of the decays I”’ -t 8 (*)n is measured to be 284 f 5 (stat.) f IS (syst.) MeV/c*. and the Gaussian width of the sigr.al is 79 f 5 (,stal.) f 8 (syst.) MeV/c2. This signal can be described as a single resonance of mass 111 = 5732 f 5 (~a!.) f ?O(syst.) McV/c’ and full width r = I45 k 28 MeV/c’. The observed shape is also consistent with the production of several broad and narrow states as predicted by the quark model and partly observed in the D-meson sector. The production rate of II** per b-jet is found to bc 0.27 f 0.02 (stat.) f 0.06 (syst.). --

1. Intmduction

This lcttcr reports on a search for orbitally excited B-meson states (II’“) in Z” -b 65 decays. t = 1 B mesons have not yet been obscrvcd cxpcrimcntally. A possible large production rate of narrow B” mesons in b-quark fragmentation has recently attracted atten-

tion [ I], since it would allow self-lagging flavour identification at production time for studies of neu- tral B mixing and searches for CP-violation al hadron colliders. Sizable D** production rates have been re- ported both in B-decays and in c-quark fragmentation by ARGUS [ 21 and CLEO [ 31, and more recently at LEP by ALEPH (41 and DELPHI [S], thus proving

that quark fragmclltation is capable of producing pri- mary mesons with orbital cxcita!ion. This motivates a search for B” states at LEI?

In the quark model one expects for each specta- tor llavour four different B meson states with orbita: angular momentum L = 1 (commonly labeled B’* or Bl,> in this paper for 6fi and bd states and ST* for bS states). The expected main decay modes of B,‘,> mesons are Bw and B*T. In this analysis B and B* mesons cannot be distinguished, therefore they are labeled as B(*). If the Bf* meson mass is above the B(*)K threshold, this will be the dominant decay mode, since B,Clr is forbidden by isospin conservation.

Heavy Quark Effective Theory (HQET) [ 61 groups these four states into two doublets per B- Flavour according to the vector sum of the lightquark’s spm and the orbital angular momentum j/ = sq + L: jf = 3/2; JF =l~,2~andj~=l/2;JP=0+,lf.The mcmhers of the first douhlct should be very narrow compared to typical strong decay widths, because only L = 2 decays are allowed. This is due to angular momentum and parity conservation for the 2+ state and a dynamical prediction for the I + partner [ 6,7]. In the D-meson sector, the two narrow states have been clearly idenlificd experimentally [2,?.8] and spin/parity and decay characteristics have been shown to be in accord with the HQET predictions.

A measurement of production of B’ mesons in 2 decays has been performed by the DELPHI [9] as well as L3 [ IO] and .QLEPH [ I I ] collaborations. The B*/B production rate and the B’ polarization ratio ar/cr~ have been found to be compatible with the spin counting expectations 3 : 1 and 2 : I. In these mea- surements the signal was obtained in the By - B mass difference spectrum, using specially developed inclu- sive B reconstruction methods. The DELPHI method serves as the basis for B** reconstruction in this paper.

The DELPHI detector is capable of studying B”’ production by using inclusively reconstructed B mesons and pion tracks originating from the primary vertex. The p&se vertex reconstruction capability of DELPHI makes it possible to efficiently tag 66 events. In the analysis that follows, an enriched sam- ple of 66 events from the 1991, 1992 and 1993 LEP runs is used. The B momentum in each hemisphere is reconstructed in an inclusive fashion, and it is com- bined with additional pions coming from the primary vertex to form the B(‘)?z signal. Measurements are

presented for the mean Q-value of transitions between L = I and ground state B-mesons as well as the 8:; production rate per b-jet. The signal is interpreted in the framework of quark model predictions.

2. The DELPHI detwtor and event selection

DEL.PHI is a 4r detector with emphasis on particle identification, three dimensional reconstruction, high granularity and precise vertex information. A com- plete description can be found in Ref. [ 121. The de- tectors most relevant to this study are the tracking chambers (Vertex Detector, Inner De!ector, Time Pro- jection Chamber and Outer Detector) and the barrel electromagnetic calorimeter (High-density Projection Chamberj. DELPHI’s vertex detector consists of three concentric shells of Si-strip detectors in the central re- gion at radii of 6.3,9 and I I cm parallel to the beam pipe for precision reconstruction near the interaction region. The algorithm that is used to enhance the 66 content, as well as the algorithm used to define the candidate track from the primary vertex for the B** decay, rely on good vertex reconstruction. Therefore, the analysis is restricted to the barrel region (45” < 0 < 135”) where there is complete vertex detector coverage. Inclusive reconstruction of the B momen- tum is based on charged and neutral particle recon- struction. The alignment of the various tracking de- tector components as well as an accurate description of efficiencies, resolutions and covariance matrix el- ements of charged tracks, which are crucial for the present analysis, have been monitored and adjusted using Z0 -+ p+p- decays and primary vertex fits of non-66 hadronic events. A momentum resolution of a(p)/p = 0.001 I . p (GeV/c) is achieved for muon pairs in the barrel region. Photons and g’s that are reconstructed by the High-density Projection Cham- ber (HPC) have a a( E)/E = 0.26/a @ 0.046 and an angular resolution of around 0.002 rad in the az- imuthal angle (b and the polar angle 8.

Using standard barrel hadronic selection [ 131, in- cluding a cut on the polar angle of the thrust axis ( 1 COS@,~,,,~,~ < C.7), I 026793 events are selected from the 1991, 1992 and 1993 data. In order lo enrich the sample in bb events, a B meson tagging algorithm exploiting the large B lifetime [ 14,151 is applied. A probability is calculated for each event assuming that

DELPHI CdaboraIinn /Physics Letrm B 345 (199s) 598-608 603

all the well-measured tracks originate from a primary vertex compatible with the beam spot. Selecting only those events where this probability is less than 1% results in an efficiency of 65 f 3% and a purity of 84 f 4% for b6 events. This beauty enhanced sample consists of : 75 960 c\:cnts.

Efficiencies, backgrounds and resolutions are cal- culated with the DELFHI simulation package, DEL- SIM, which uses the JETSET 7.3 Monte Carlo gener- ator [ 161 with parameter adjustments from previous QCD studies [ 171. The B* - B mass difference in the JETSET generator was fixed to the current Particle Data Group world average. In addition, special Monte Carlo samples including production and decay of B** mesons have been generated using masses, widths and decay modes as predicted by HQET [ 181.

3. Inclusive B rwonstruction

The B meson momenttim is reconstructed using the same algorithm [ 191 that is used in the DELPHI B’ analysis [ 91. The events are divided into hemispheres defined by the thrust axis. The rapidity of each recon- structed charged (assuming pion mass) and neutral particle (assuming photon mass) with respect lo the thrust axis is calculated. The particles whose rapidi- ties are outside a window of fl.5 units are considered to be B meson decay products. The momenta of these particles are added together in each hemisphere to ar- rive at a B meson momentum estimate for each side of the event. This raw B energy is corrected by using the reconstructed raw invariant mass my and the ratio of the energy seen in the hemisphere to the beam energy (xh = Ekhspkre/Ebepm). The invariant mass is set to the current mass value for the B meson [ 81. Details of this procedure can be found in [9]. To reduce the amount of badly reconstructed B-mesons a minin;.,m reconstructed energy of 20 GeV in the rapidity gather- ing algorithm is required, and the reconstructed mass has to lie within f2.5 GeV/c* of the mean recon- structed B meson mass. This algorithm is only mean- ingful in two jet events and for the most energetic jet in three jet events. These have been identified using the LUCLUS algorithm [ 161 with a transverse mo- mentum cutoff of 3.5 GeV/c.

Using the simulation sample, the energy resolution of this inclusive technique is determined to be 7%

for 70% of the B mesons (the rect constitute a non- Gaussian tail towards higher &mated energies); the angular resolutions in 8 and 4 can be parameterized as double Gaussians with widths 0.015 rad for 60% of the data and 0.038 rad for the remaining 40%. fie insiusive rapidity distributions for charged and neutrai particles as well as the distributions of reconstructed B mass and reconstructed B energy observed in the data agree very well with the Monte Carlo expecta- tions [9]. The simulation prediction of the resolutions of the inclusive B reconstruction algorithm is verified by the good agreement in the width of the B* -+ By mass difference peak [ 91.

4. Experimental prucedulp and results

If the mass of B** mesons is above the B*w but be- low the Bp threshold, 3” mesons mainly decay into Bw or S’rr. Parity conservation restricts the expected main decay modes of the single states: the spin-parity state O+ would decay into Ba (s-wave), the two I+ states into B*lr (s- (:r d-wave), and the 2+ state into both BT and E*P (both d-wave). Positively charged pions can come from decays of the f~ = +I/2 states B **+ (containing a &quark) and 8**O (containing a bquark). Therefore, flavour tagging with e.g. inclu- sive leptons or jet charge cannot be used lo enhance the ratio of B‘” signal to background.

Both the B decay particles as well as the B” de- cay pion have large rapidities. However, since the B*+ decays strongly, the pion should originate from the primary vertex and not from the B decay vertex.

The quantity which is best accessible experimen- tally with inclusive B reconstruction methods is the Q-value of the decay:

Q = m( B(*)n) - m( B”‘) - m(n)

z m( B*‘) - m( B”‘) - m(r).

The symbol B(*) denotes both B and B’ states, which cannot be distinguished with the present method. The resolution of the present method can be parameterized as a(Q) = 18 MeV/c*+ 65 MeV/c* x (Q [GeV/c*]). It is dominated by the energy and angular resolution of the B-meson. Whether the decay was actually into B or B* and whether the B* decay photon has been reconstructed,

604 DELPHI Collaborarion / Plt,ssic.s Lenem B 345 (1995) 598-608

only has a negligible effect on the resolution in the Q- value. However, the decay of a B** of a given mass to a B*T gives rise to a Q-value which is shifted down- wards by the B’ - B III~SS diffeicncc of 45 MeVlc’ compared to the Q-value of a BIT decay. Therefore, for the determination of a 1‘3** mass from the measur- able Q-value, an assumption about the B*/B ratio in the signal has to be employed.

Pion tracks are selected which are compatible with the primary vertex and not with a secondary B decay vertex. This is accomplished by the following algo- rithm. All well measured tracks with at least two vertex detector hits associated are classified into three ver- tices: the primary vertex which has to br compatible with the known beam spot, and two B decay vertices. The rapidity classification serves as a starting point: all particles with 1.~1 < I .5 are assigned to the primary vertex, and those with y < -I 5 and y > I.5 to the two secondary vertices. Three vertex fits are then per- formed. The track coritributing the largest x’ is then tried at the other kinematically allowed vertex (i.e. the primary vertex if it was a secondary before and vice versa). The new vertex distribution is accepted if the x2 gets better, otherwise the old distribution is kept. If the track gives the largest x2 contribution in both situations, it is discarded. This procedure is continued until no track gives a ,$ contribution larger than 4. For the B*’ pion candidates, only tracks fitted to the primary vertex ate accepted.

In order to get a clear distinction between primary and secondary vertices, the reconstructed decay length (in the signal hemisphere) is required to exceed 1.5 mm. A further reduction of tracks from B decays can be achieved by requiring a value of less than 1% for the probability that all the particles in the signal hemi - sphere stem from the primary vertex. An additional selection is performed on the lifetime-signed impact parameter of the pion candidate tracks: if the lifetime- signed impact parameter of the candidate pion with respect to the primary vertex is positive, then the x2 probability that it originates from the primary vertex has to be larger than 15%.

The distribution of the measured B(*)n Q-values is shown as data points in Fig. la. There is a large tixcess of combinations on top of a smoothly falling background. The background i; well described by the Monte Carlo prediction, in which B”” decay pions have been suppressed, shown as shaded area in Fig. la.

2 = 1200 Fi

\ 3 loo0 c ii

0600

600

400

200

0

tl , I , , I I ,‘t L3s I I I ,1 I ) i L

0 0.2 0.4 0.6 0.6 1 1.2 1.4 Q(El%) / GeV

Fig. 1. (a) Distribution of the Q-value of !I(*) n pairs (data points) along wirh the Monte Carlo expectation without B** production (shaJedarea).Q is defined~Q=m(Bt’)*)-,n(B”))-,r~(n).

(b) Backgroad subtracted 6”) T pair Q-value distribution. The fit is tt simple Gaussian,

The Monte Carlo statistics is comparable to the data statistics. Fig. 1 b shows the difference plot, which is fit to a simple Gaussian with central value

Q(B** -+ B’*‘T) = 254 f 5 (stat.) f 15 (syst.) MeV/c2

and Gaussian width

c = 79 f 5 (stat.) f 8 (syst.) MeV/c’

containing

N = 2157 f 120(stat.) f 323 (syst.)

events. This corresponds to a statistical significance of 18 standard deviations. Systematic uncertainties dorn- inate in the measurements of all these quantities. They

DELPHI Colhbmion /Physics Letters B 345 (1995) S98-608 605

were determined by modifying cuts and by fitting dif- ferent background shapes (originating from simula- tion and various phenomenological background mod- els) to the data. Employing the simulation predic- tion for the background shape, the normalization had to be adjusted by the factor 0.95 f 0.01 (stat.) f 0.04 (syst., dependence on cuts) in order to describe the data well at large Q-values.

Possible reflections from B,z* -+ B’*)fc decays are expected to contribute in the Q-value range between 50 and 250 MeV/c* at the level of 10% to the ex- P-4 Bu*.+d signal. Additional uncertainties are intro- duced by the possible production of zb -+ Able and reflections from the decay Bl,> -+ B’*)p. Their pos- sible influence has been considered in evaluating the systematic errors.

To check whether the signal could be an artifact of the employed vertex procedure, the selection cuts were varied within wide ranges. Also using simple analysis techniques without vertex fitting, a clear excess with the same characteristics is observed, but on top of a larger combinatorial background.

Furthermore the charge symmetry of the signal was tested by dividing the sample according to positive and negative pion charge, positive and negative jet charge, and positive and negative product of jet and pion charge. The jet charge was defined as (Qpt,,, - QjeLOppO ), where the Qj,t Ci Qi . P,“‘“/ C; PQ’

were calculated using Qjet = in the signal hemisphere (ex-

cluding the candidate pion) and in the opposite hemi- sphere. In all these cases the rates are compatible with the Monte Carlo prediction.

All tests have been passed successfully, no cut being found where the behaviour of the data was different from that expected from the simulation prediction for a strongly decaying isospin l/2 B(*)lr resonance.

The total BiJ rate is determined to be

uRJJ /u&jet = 0.27 k 0.02 (Stat.) f 0.06 (SYS!.).

In this rate calculation it was assumed that 2/3 of all B” decay into charged pions and l/3 into (un- observed) rr”, according to isospin rules for an I = l/2 decay into an isovector and an isospinor. Different cuts on the 6 reconstruction quality and the candidate pion selection have been used. The largest systematic uncertainty ( f 0.03) was observed -.vhen dividing the event sample into two hemispheres defined by the an-

gle of the pion in the B** rest frame with respect to the B** flight ciircction (helicity angle). Including the limited Monte Carlo statistics, the systematic error of the acceptance calculation is estimated to be It 15%.

From this the total number of B,;,:, mesons per hadronic 2 decay is determined to he

NB;,,;/ZI,~~ = 0. I18 f 1.007 (stat.) * 0.023 (syst.).

Assuming the b-bar! , I ate to be IO & 4 % and the Bj*’ rate to Lz I3 f 2 %, the relative amount of Bu.d mesons which originate from Bu+,> decay is

WI,;; ln?un = 0.35 i 0.02 (stat.) f 0.08 (syst.).

5. Interpretation of the signal

If the signal were due to a single very narrow reso- nance, the expected Gaussian width would be around u = 38 MeV/c*, as shown in Fig. 2a. This can clearly be excluded. In order to describe the much broader observed signal with a single resonance, its full width would have to be

r = 145 f 28 MeV/c*.

The signal would be broadened if different reso- nances with different masses cortribute, and some decay into B?r and others into B*R, leading to a 45 MeV/c* shift in Q-value. The observed signal shape is consistent with predictions for orbital ex- citations [ 181. According to this model the signal would consist of two narrow (l+ and 2+) and two broad (O+ and 1’) resonances of roughly the same mass (splittings at the 10 MeV/c* level), decaying into B’a or Brr, as dictated by spin-parity rules. The 2+ is predicted to decay into both B*T and Brr with about equal rates.

There is no prediction about the relative production rates of the four B”* states, but reasonable assumptions range between 5 : 3 : 3 : 1 (spin counting) and 1 : 1 : 1 : 1 (state counting) for the 2+ .: I+ : I+ : O+ states. In the D meson sector the production ratio of 0; + DIT io D; - D’a to DI --) D’n has been measured by CLEO [3] to be roughly 2 : 1 : 3. This is compatible with :he state counting picture for the narrow states. It also confirms the D,’ + Dir : 0; --) D*R = 1.8 : 1 decay branching ratio prediction from

606 DELPHI Colluboration / Physics Lettx~ B 345 (1995) 598&M

0 0.2 0.4 0.6 0 0.2 0.4 0.6

Q(E(%) / GeV

Fig. 2. Comparison of Ihe background subtracted Q-v;llue distribution (data points) with various models (solid line). The shaded ~JIXI

cormsponds to the generated distribution (scaled by a factor 0.2) prior to detector resolution effect< : (a) a delta-function 31 Q = 284 MaVlc? (detector resolution including non-Gaur.sim tails). (b) two narrow resonances, one decaying into Bn, the other equally into Br

and B’n. A mass splitting of 80 MeVlc2 is necessary to descri’x the observed width. (c) the model of Eichten et al. [ 181, plus broad resonances shifted downward\ by 50 MeV/c?. (d) two narrow .md two broad states without large mass splitting

qQET 1181. These facts motivate the use of state counting and HQET predictions.

An interpretation of the signal as stemming from 0~1~ narrow resonances (of width r x 20 MeV/c’) is unlikely. If the mass splitting were small, the ob- servable signal width would be only 46 MeV/c2; for splittings in the order of 35 MeVlc2 (as in the D me- son s&or) it is expected to be 52 MeV/c2. To achieve a signal with the observed width, a splitting of 8C PdcV/c2 would be necessary, as shown in Fig. 2b. In this case, the experimental resolution shuzld start to reso!ve a substructure. The expectation for this model does not describe the data well. Also, such a large splitting is not expected [ 181. Therefore the observed signal should also contain broad resonances with c* full width r of about 150 MeV/c?.

The data is compared to a model based on masses and widths for the narrow states as predicted from the HQET model of Eichten et al. [ 181. Further assump- tions are that the two broad states have a width of 150 MeV/c’ and that thz four B”‘ states are produced in a ratio of I : I : I : 1. Assuming the broad reso- nances to have the same mass as the narrow onzs does not describe the data well; therefore they have been shifted downwards by 50 MeV/c2 and their rate has been increased by 50% for Fig. 2c. Such an energy splitting between the j, = 3/2 and I /2 states has been proposed by Rosner [ 71. The agreement between data and simulation wouid be better by slightly lowering the masses of the narrow states.

Assuming a B’lr to B?r ratio of 2 : I, the mean mass difference between the B meson and the cross

DELPHI Collabaratim / f’l~ysics Letters B 335 (1995) 598608 607

section weighted mean of the four expected B,:,> res- onances is determined to be M( B,;,:,) - M( B,,.,I) = 453 f 5 (stat.) f 20 (syst.) MeV/c’, corresponding to a mass

M( Bi,T,j = 5732 +I 5 (stat.) & 20 (syst.) MeVlc?.

Part of the systematic error is due to the uncertainty in the ratio of decays into 8’ and B in the mapping from Q-value to mass difference; it can accommodate for the two reasonable assumptions I : 1 and 3 : i. This value is consistent with the predicted 488 McV/c2 for the B; - B and 476 MeVfc’ for the BI - B mass differences [ 181.

Fig. 2d is an attempt to describe the data without a large mass splitting between narrow and broad states. In this case, the mean mass difference as determined above and a mass splitting between the narrow states of 20 MeV/c2 is used. The ratio of the broad to narrow states is 3 : 2, an even larger contribution of the broad states would make the agreement better.

Wtth the current experimental sensitivity the inter- pretations in Fig. 2c and d Fannot be distinguished, nei- ther can one of them be discarded. The simple Gaus- sian fit shown in Fig. I b describes the data best. How- ever, due to the large freedom, consistent results can be achieved in a number of possible scenarios based on quark model and HQET.

6. Summary and conclusions

Strong experimental evidence for the ~xI:.:.. :.. C‘ r!t orbitally excited B-mesons (B,:j) has been obtained from the B’*)rQ-value distribution using an inclusive B reconstruction method and separating primary and secondary vertices with the DELPHI silicon vertex detector.

The B’*)tr Q-value distribution shows a large sig- nal at Q = 284 f 5 (stat.) f 15 (syst.) MeV/c2 with a Gaussian width of a(Q) = 79 f 5 (stat.) ZIZ 8 (syst.) MeV/c2. The signal can be described as a single res- onance of mass m = 5732 f 5 (stat.) f 20 (syst.) MeV/c* and full width I‘ = 145 f 28 MeV/c*. It can also be interpreted as stemming from several nar- row and broad predicted B,‘.:, resonances, as predicted by quark models and HQET and observed in the D

meson z;ctor. The rate of B;; mesons per b-jet is 0.27 f 0.02 (stat.) ZIZ 0.06 (syst.).

In conclusion, the existence of orbitally excited B mesons has been experimentally established. The re- sults are in general agreement with predictions.

During the process of refereeing we learned about a paper by the OPAL Collaboration [ 201 which also shows evidence for B** production.

Acknowledgements

We are greatly indebted to our technical collabora- tors and to the funding agencies for their support in building and operating the DELPHI detector, and to the members of the CERN-SL Division for the excel- lent performance of the LEP collider.

References

I 1 I M. Gronau. A. Nippe and J.L. Rosner. Phys. Rev. D 47 ( 1993) I988

121 ARGUS Collaboration, H. Albrecht ct al.. Phys. Lea. B 221 ( 1989) 422, ARGUS Collaboration. H. Albrecht et al.. Phys. Lett. B 232 ( 1989) 398

13 I CLEO Coll&ontion. P. Avery et al.. Phys. Rev. D 41 ( 1990) 774 CLEO Coll&ontion. P. Avery et al., Phys. Lctt. B 331 (1994) 236 CLEO CoIabomtion. E Butler et al.. Observation of DI (2430)+ and D;(2470)+, contributed paper to the International Conference on High Energy Physics. Glasgow

1994, ref. gls0 I85 141 ALEPH Coll:thorntion, I)‘* Production in Z” Decays,

contributed paper to the International Conference on High Energy Physics. Glasgow 1994. ref. &OS77

IS] DELPHI Collaboration. Study of D. D’ and D” Production in Z” Hadronic Decays. contributed papcrto the International Conference on High Energy Physics. G!nsgow 1994. ref.

glsOl85 161 N. Isgur, M.B. Wise, Phys. Lett. B 232 (1989) 113;

M.B. Wise, Procs. XVI International Symposium on Lepton and Photon Interactions. Ithaca, New York. 1993. Ed. P Drell. D. Rubin. p. 2.53.

171 J.L. Rosner, Comm. Nucl. Part. Phys. 16 ( 1986) 109 18 I Particle Data Group, Phys. Rev. D SO ( 1994) I 173 191 DELPHI Collaboration, DELPHI Note 94-80 Phys 397;

contributed paper IO the International Conference on High Energy Physics, Glasgow 1994. ref. glsO305; DELPHI draft 103, to be published

[ lOI L3 Collabontion, M. Acckri et al.. CERN-PPE/94-I43

(1994)

608 DELPHI Collaboration /Physics Lerms B 345 (1995) 598+508

] II ] ALEPH Collaboration. A study of 8’ Production in Z Il6! T. Sjiistrand. Comp. Phys. Comm. 39 (1986) 347; Decays, contributed paper IO the International Conference T. Sjijstrand and M. Bengtsson, Comp. Phys. Comm. 43 on High Energy Physics, Glasgow 1994. ref. glsO598 ( 1987) 367

] 121 DELPHI Collaboration, P. Aamio et al.. Nucl. Instr. Meth. ] ! 7) W. de Boer, H. Fiirstenau. Comparison of DELPHI data with A 303 ( 1991) 233-276 QCD modeIs. Delphi Note 91-75 Phys 129

] I3 ] DELPHI Collaboration. P Abreu et al . Z. Phys. C 54 ( 1992) ] IS] E.J. Eichtxr, C.T. Hill and C. Quigg. Phys. Rev. Lett. 71 55 (1993) 4116

] 141 ALEPH Co!lnboration, D. Buskulic et al.. Phys. Len. B 3 I3 ] 191 0. PJdobrin, An algorithm for inclusive /J hadron (1993) 535 reconstruction, DELPHI note. in pteparatron

] I5 ] DELPHI Collaboration, P Abreu ::i al., CERN-PPE-94-131 [201 OPAL Collaboration, R. Akem et al.. CERN-PPE-94-206