Measurements of the Branching Fractions of Exclusive Charmless B Meson Decays with Eta-prime and Omega Mesons

Measurements of the Branching Fractions of Exclusive Charmless

B

Meson Decays

with

h

or

v

Mesons

B. Aubert,1_{D. Boutigny,}1_{J.-M. Gaillard,}1_{A. Hicheur,}1_{Y. Karyotakis,}1_{J. P. Lees,}1_{P. Robbe,}1_{V. Tisserand,}1 A. Palano,2_{G. P. Chen,}3_{J. C. Chen,}3_{N. D. Qi,}3_{G. Rong,}3_{P. Wang,}3_{Y. S. Zhu,}3_{G. Eigen,}4_{P. L. Reinertsen,}4_{B. Stugu,}4 B. Abbott,5_{G. S. Abrams,}5_{A. W. Borgland,}5_{A. B. Breon,}5_{D. N. Brown,}5_{J. Button-Shafer,}5_{R. N. Cahn,}5_{A. R. Clark,}5

M. S. Gill,5_{A. Gritsan,}5_{Y. Groysman,}5_{R. G. Jacobsen,}5_{R. W. Kadel,}5_{J. Kadyk,}5 _{L. T. Kerth,}5_{S. Kluth,}5 Yu. G. Kolomensky,5J. F. Kral,5C. LeClerc,5M. E. Levi,5T. Liu,5G. Lynch,5A. B. Meyer,5M. Momayezi,5 P. J. Oddone,5_{A. Perazzo,}5_{M. Pripstein,}5_{N. A. Roe,}5_{A. Romosan,}5_{M. T. Ronan,}5_{V. G. Shelkov,}5_{A. V. Telnov,}5 W. A. Wenzel,5_{P. G. Bright-Thomas,}6_{T. J. Harrison,}6_{C. M. Hawkes,}6_{D. J. Knowles,}6_{S. W. O’Neale,}6_{R. C. Penny,}6

A. T. Watson,6N. K. Watson,6T. Deppermann,7K. Goetzen,7H. Koch,7J. Krug,7M. Kunze,7B. Lewandowski,7 K. Peters,7_{H. Schmuecker,}7_{M. Steinke,}7_{J. C. Andress,}8_{N. R. Barlow,}8_{W. Bhimji,}8_{N. Chevalier,}8_{P. J. Clark,}8

W. N. Cottingham,8N. De Groot,8N. Dyce,8B. Foster,8 J. D. McFall,8D. Wallom,8F. F. Wilson,8K. Abe,9 C. Hearty,9_{T. S. Mattison,}9_{J. A. McKenna,}9_{D. Thiessen,}9_{S. Jolly,}10_{A. K. McKemey,}10_{J. Tinslay,}10 _{V. E. Blinov,}11

A. D. Bukin,11D. A. Bukin,11 A. R. Buzykaev,11 V. B. Golubev,11V. N. Ivanchenko,11A. A. Korol,11 E. A. Kravchenko,11_{A. P. Onuchin,}11 _{A. A. Salnikov,}11 _{S. I. Serednyakov,}11 _{Yu. I. Skovpen,}11 _{V. I. Telnov,}11 A. N. Yushkov,11 _{D. Best,}12 _{A. J. Lankford,}12_{M. Mandelkern,}12_{S. McMahon,}12 _{D. P. Stoker,}12_{A. Ahsan,}13 K. Arisaka,13 _{C. Buchanan,}13_{S. Chun,}13 _{J. G. Branson,}14 _{D. B. MacFarlane,}14 _{S. Prell,}14_{Sh. Rahatlou,}14 _{G. Raven,}14

V. Sharma,14_{C. Campagnari,}15 _{B. Dahmes,}15 _{P. A. Hart,}15 _{N. Kuznetsova,}15 _{S. L. Levy,}15 _{O. Long,}15 _{A. Lu,}15 J. D. Richman,15 W. Verkerke,15M. Witherell,15 S. Yellin,15J. Beringer,16 D. E. Dorfan,16A. M. Eisner,16 A. Frey,16

A. A. Grillo,16 _{M. Grothe,}16 _{C. A. Heusch,}16 _{R. P. Johnson,}16_{W. Kroeger,}16 _{W. S. Lockman,}16_{T. Pulliam,}16 H. Sadrozinski,16 T. Schalk,16R. E. Schmitz,16 B. A. Schumm,16 A. Seiden,16 M. Turri,16 W. Walkowiak,16 D. C. Williams,16 _{M. G. Wilson,}16_{E. Chen,}17 _{G. P. Dubois-Felsmann,}17 _{A. Dvoretskii,}17 _{D. G. Hitlin,}17 _{S. Metzler,}17

J. Oyang,17 F. C. Porter,17A. Ryd,17 A. Samuel,17M. Weaver,17 S. Yang,17 R. Y. Zhu,17S. Devmal,18T. L. Geld,18 S. Jayatilleke,18_{G. Mancinelli,}18 _{B. T. Meadows,}18 _{M. D. Sokoloff,}18_{T. Barillari,}19 _{P. Bloom,}19 _{M. O. Dima,}19 S. Fahey,19 _{W. T. Ford,}19 _{T. L. Hall,}19_{D. R. Johnson,}19_{U. Nauenberg,}19 _{A. Olivas,}19 _{H. Park,}19_{P. Rankin,}19_{J. Roy,}19 S. Sen,19 J. G. Smith,19 W. C. van Hoek,19 D. L. Wagner,19J. Blouw,20 J. L. Harton,20 M. Krishnamurthy,20 A. Soffer,20

W. H. Toki,20_{R. J. Wilson,}20_{J. Zhang,}20_{T. Brandt,}21 _{J. Brose,}21_{T. Colberg,}21_{G. Dahlinger,}21 _{M. Dickopp,}21 R. S. Dubitzky,21 E. Maly,21 R. Müller-Pfefferkorn,21S. Otto,21 K. R. Schubert,21R. Schwierz,21B. Spaan,21 L. Wilden,21_{L. Behr,}22_{D. Bernard,}22_{G. R. Bonneaud,}22_{F. Brochard,}22 _{J. Cohen-Tanugi,}22_{S. Ferrag,}22_{E. Roussot,}22 S. T’Jampens,22C. Thiebaux,22G. Vasileiadis,22 M. Verderi,22A. Anjomshoaa,23R. Bernet,23A. Khan,23F. Muheim,23

S. Playfer,23 _{J. E. Swain,}23_{M. Falbo,}24 _{C. Borean,}25 _{C. Bozzi,}25 _{S. Dittongo,}25_{M. Folegani,}25 _{L. Piemontese,}25 E. Treadwell,26_{F. Anulli,}27,_{* R. Baldini-Ferroli,}27_{A. Calcaterra,}27 _{R. de Sangro,}27_{D. Falciai,}27 _{G. Finocchiaro,}27 P. Patteri,27 _{I. M. Peruzzi,}27,_{* M. Piccolo,}27_{Y. Xie,}27 _{A. Zallo,}27_{S. Bagnasco,}28_{A. Buzzo,}28 _{R. Contri,}28 _{G. Crosetti,}28

P. Fabbricatore,28 _{S. Farinon,}28 _{M. Lo Vetere,}28 _{M. Macri,}28_{M. R. Monge,}28 _{R. Musenich,}28_{M. Pallavicini,}28 R. Parodi,28 S. Passaggio,28 F. C. Pastore,28 C. Patrignani,28M. G. Pia,28C. Priano,28 E. Robutti,28A. Santroni,28 M. Morii,29 _{R. Bartoldus,}30_{T. Dignan,}30 _{R. Hamilton,}30 _{U. Mallik,}30_{J. Cochran,}31_{H. B. Crawley,}31 _{P.-A. Fischer,}31 J. Lamsa,31_{W. T. Meyer,}31_{E. I. Rosenberg,}31 _{M. Benkebil,}32_{G. Grosdidier,}32 _{C. Hast,}32 _{A. Höcker,}32 _{H. M. Lacker,}32

V. LePeltier,32 A. M. Lutz,32 S. Plaszczynski,32M. H. Schune,32 S. Trincaz-Duvoid,32 A. Valassi,32 G. Wormser,32 R. M. Bionta,33 _{V. Brigljevic´,}33_{D. J. Lange,}33_{M. Mugge,}33 _{X. Shi,}33 _{K. van Bibber,}33_{T. J. Wenaus,}33_{D. M. Wright,}33

C. R. Wuest,33M. Carroll,34 J. R. Fry,34E. Gabathuler,34 R. Gamet,34M. George,34M. Kay,34 D. J. Payne,34 R. J. Sloane,34 _{C. Touramanis,}34_{M. L. Aspinwall,}35_{D. A. Bowerman,}35_{P. D. Dauncey,}35_{U. Egede,}35 _{I. Eschrich,}35

N. J. W. Gunawardane,35J. A. Nash,35 P. Sanders,35D. Smith,35 D. E. Azzopardi,36J. J. Back,36 P. Dixon,36 P. F. Harrison,36_{R. J. L. Potter,}36 _{H. W. Shorthouse,}36 _{P. Strother,}36 _{P. B. Vidal,}36 _{M. I. Williams,}36_{G. Cowan,}37 S. George,37_{M. G. Green,}37 _{A. Kurup,}37_{C. E. Marker,}37_{P. McGrath,}37_{T. R. McMahon,}37_{S. Ricciardi,}37 _{F. Salvatore,}37 I. Scott,37G. Vaitsas,37D. Brown,38C. L. Davis,38J. Allison,39R. J. Barlow,39J. T. Boyd,39A. C. Forti,39J. Fullwood,39

F. Jackson,39 _{G. D. Lafferty,}39 _{N. Savvas,}39 _{E. T. Simopoulos,}39_{J. H. Weatherall,}39_{A. Farbin,}40_{A. Jawahery,}40 V. Lillard,40 J. Olsen,40 D. A. Roberts,40 J. R. Schieck,40 G. Blaylock,41 C. Dallapiccola,41 K. T. Flood,41 S. S. Hertzbach,41_{R. Kofler,}41 _{T. B. Moore,}41 _{H. Staengle,}41_{S. Willocq,}41 _{B. Brau,}42_{R. Cowan,}42_{G. Sciolla,}42 F. Taylor,42_{R. K. Yamamoto,}42_{M. Milek,}43 _{P. M. Patel,}43 _{J. Trischuk,}43 _{F. Lanni,}44_{F. Palombo,}44 _{J. M. Bauer,}45 M. Booke,45 L. Cremaldi,45V. Eschenburg,45R. Kroeger,45 J. Reidy,45D. A. Sanders,45 D. J. Summers,45J. P. Martin,46

J. Y. Nief,46_{R. Seitz,}46 _{P. Taras,}46_{V. Zacek,}46 _{H. Nicholson,}47 _{C. S. Sutton,}47_{C. Cartaro,}48 _{N. Cavallo,}48,†

G. De Nardo,48F. Fabozzi,48C. Gatto,48 L. Lista,48 P. Paolucci,48 D. Piccolo,48 C. Sciacca,48 J. M. LoSecco,49 J. R. G. Alsmiller,50 _{T. A. Gabriel,}50_{T. Handler,}50 _{J. Brau,}51_{R. Frey,}51 _{M. Iwasaki,}51_{N. B. Sinev,}51 _{D. Strom,}51 F. Colecchia,52F. Dal Corso,52A. Dorigo,52F. Galeazzi,52M. Margoni,52G. Michelon,52M. Morandin,52M. Posocco,52

M. Rotondo,52 _{F. Simonetto,}52 _{R. Stroili,}52_{E. Torassa,}52 _{C. Voci,}52 _{M. Benayoun,}53_{H. Briand,}53_{J. Chauveau,}53 P. David,53 _{C. De la Vaissière,}53 _{L. Del Buono,}53_{O. Hamon,}53 _{F. Le Diberder,}53_{Ph. Leruste,}53_{J. Lory,}53 _{L. Roos,}53 J. Stark,53 S. Versillé,53P. F. Manfredi,54V. Re,54V. Speziali,54E. D. Frank,55L. Gladney,55Q. H. Guo,55J. H. Panetta,55

C. Angelini,56 _{G. Batignani,}56 _{S. Bettarini,}56_{M. Bondioli,}56_{M. Carpinelli,}56 _{F. Forti,}56 _{M. A. Giorgi,}56_{A. Lusiani,}56 F. Martinez-Vidal,56M. Morganti,56 N. Neri,56 E. Paoloni,56M. Rama,56 G. Rizzo,56 F. Sandrelli,56 G. Simi,56 G. Triggiani,56 _{J. Walsh,}56_{M. Haire,}57 _{D. Judd,}57 _{K. Paick,}57 _{L. Turnbull,}57_{D. E. Wagoner,}57_{J. Albert,}58 _{C. Bula,}58 P. Elmer,58 C. Lu,58K. T. McDonald,58V. Miftakov,58S. F. Schaffner,58 A. J. S. Smith,58A. Tumanov,58 E. W. Varnes,58

G. Cavoto,59 _{D. del Re,}59_{R. Faccini,}14,59 _{F. Ferrarotto,}59 _{F. Ferroni,}59 _{K. Fratini,}59 _{E. Lamanna,}59 _{E. Leonardi,}59 M. A. Mazzoni,59 _{S. Morganti,}59 _{G. Piredda,}59 _{F. Safai Tehrani,}59 _{M. Serra,}59 _{C. Voena,}59 _{S. Christ,}60_{R. Waldi,}60 T. Adye,61_{B. Franek,}61_{N. I. Geddes,}61_{G. P. Gopal,}61 _{S. M. Xella,}61 _{R. Aleksan,}62_{G. De Domenico,}62_{S. Emery,}62

A. Gaidot,62_{S. F. Ganzhur,}62_{P.-F. Giraud,}62 _{G. Hamel de Monchenault,}62 _{W. Kozanecki,}62 _{M. Langer,}62 G. W. London,62 _{B. Mayer,}62 _{B. Serfass,}62 _{G. Vasseur,}62 _{C. Yeche,}62_{M. Zito,}62_{N. Copty,}63 _{M. V. Purohit,}63 H. Singh,63 _{F. X. Yumiceva,}63_{I. Adam,}64 _{P. L. Anthony,}64 _{D. Aston,}64 _{K. Baird,}64 _{E. Bloom,}64_{A. M. Boyarski,}64 F. Bulos,64_{G. Calderini,}64_{R. Claus,}64_{M. R. Convery,}64 _{D. P. Coupal,}64 _{D. H. Coward,}64_{J. Dorfan,}64 _{M. Doser,}64

W. Dunwoodie,64R. C. Field,64 T. Glanzman,64 G. L. Godfrey,64 S. J. Gowdy,64 P. Grosso,64 T. Himel,64 M. E. Huffer,64_{W. R. Innes,}64 _{C. P. Jessop,}64 _{M. H. Kelsey,}64 _{P. Kim,}64 _{M. L. Kocian,}64 _{U. Langenegger,}64 D. W. G. S. Leith,64 S. Luitz,64 V. Luth,64 H. L. Lynch,64H. Marsiske,64S. Menke,64R. Messner,64 K. C. Moffeit,64 R. Mount,64 _{D. R. Muller,}64 _{C. P. O’Grady,}64 _{M. Perl,}64 _{S. Petrak,}64_{H. Quinn,}64_{B. N. Ratcliff,}64_{S. H. Robertson,}64 L. S. Rochester,64 A. Roodman,64 T. Schietinger,64R. H. Schindler,64J. Schwiening,64 V. V. Serbo,64A. Snyder,64

A. Soha,64 _{S. M. Spanier,}64_{J. Stelzer,}64 _{D. Su,}64_{M. K. Sullivan,}64 _{H. A. Tanaka,}64_{J. Va’vra,}64 _{S. R. Wagner,}64 A. J. R. Weinstein,64 _{W. J. Wisniewski,}64 _{D. H. Wright,}64_{C. C. Young,}64 _{P. R. Burchat,}65_{C. H. Cheng,}65 _{D. Kirkby,}65

T. I. Meyer,65C. Roat,65 R. Henderson,66W. Bugg,67 H. Cohn,67 A. W. Weidemann,67 J. M. Izen,68I. Kitayama,68 X. C. Lou,68 _{M. Turcotte,}68_{F. Bianchi,}69_{M. Bona,}69 _{B. Di Girolamo,}69 _{D. Gamba,}69 _{A. Smol,}69 _{D. Zanin,}69

L. Lanceri,70 A. Pompili,70 G. Vuagnin,70 R. S. Panvini,71 C. M. Brown,72A. De Silva,72 R. Kowalewski,72 J. M. Roney,72 _{H. R. Band,}73_{E. Charles,}73 _{S. Dasu,}73_{F. Di Lodovico,}73 _{A. M. Eichenbaum,}73_{H. Hu,}73 _{J. R. Johnson,}73 R. Liu,73 J. Nielsen,73 Y. Pan,73R. Prepost,73 I. J. Scott,73S. J. Sekula,73 J. H. von Wimmersperg-Toeller,73S. L. Wu,73

Z. Yu,73 _{H. Zobernig,}73 _{T. M. B. Kordich,}74 _{and H. Neal}74 (TheBABARCollaboration)

1_{Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France} 2_{Università di Bari, Dipartimento di Fisica and INFN, I-70126 Bari, Italy}

3_{Institute of High Energy Physics, Beijing 100039, China} 4_{University of Bergen, Institute of Physics, N-5007 Bergen, Norway}

5_{Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720} 6_{University of Birmingham, Birmingham, B15 2TT, United Kingdom}

7_{Ruhr Universität Bochum, Institut für Experimentalphysik 1, D-44780 Bochum, Germany} 8_{University of Bristol, Bristol BS8 1TL, United Kingdom}

9_{University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1} 10_{Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom}

11_{Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia} 12_{University of California at Irvine, Irvine, California 92697} 13_{University of California at Los Angeles, Los Angeles, California 90024}

14_{University of California at San Diego, La Jolla, California 92093} 15_{University of California at Santa Barbara, Santa Barbara, California 93106}

16_{University of California at Santa Cruz, Institute for Particle Physics, Santa Cruz, California 95064} 17_{California Institute of Technology, Pasadena, California 91125}

18_{University of Cincinnati, Cincinnati, Ohio 45221} 19_{University of Colorado, Boulder, Colorado 80309} 20_{Colorado State University, Fort Collins, Colorado 80523}

21_{Technische Universität Dresden, Institut für Kern und Teilchenphysik, D-01062, Dresden, Germany} 22_{Ecole Polytechnique, F-91128 Palaiseau, France}

24_{Elon College, Elon College, North Carolina 27244-2010}

25_{Università di Ferrara, Dipartimento di Fisica and INFN, I-44100 Ferrara, Italy} 26_{Florida A&M University, Tallahassee, Florida 32307}

27_{Laboratori Nazionali di Frascati dell’INFN, I-00044 Frascati, Italy} 28_{Università di Genova, Dipartimento di Fisica and INFN, I-16146 Genova, Italy}

29_{Harvard University, Cambridge, Massachusetts 02138} 30_{University of Iowa, Iowa City, Iowa 52242} 31_{Iowa State University, Ames, Iowa 50011-3160} 32_{Laboratoire de l’Accélérateur Linéaire, F-91898 Orsay, France} 33_{Lawrence Livermore National Laboratory, Livermore, California 94550}

34_{University of Liverpool, Liverpool L69 3BX, United Kingdom} 35_{University of London, Imperial College, London, SW7 2BW, United Kingdom}

36_{Queen Mary, University of London, E1 4NS, United Kingdom}

37_{University of London, Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, United Kingdom} 38_{University of Louisville, Louisville, Kentucky 40292}

39_{University of Manchester, Manchester M13 9PL, United Kingdom} 40_{University of Maryland, College Park, Maryland 20742} 41_{University of Massachusetts, Amherst, Massachusetts 01003}

42_{Massachusetts Institute of Technology, Lab for Nuclear Science, Cambridge, Massachusetts 02139} 43_{McGill University, Montréal, Canada QC H3A 2T8}

44_{Università di Milano, Dipartimento di Fisica and INFN, I-20133 Milano, Italy} 45_{University of Mississippi, University, Mississippi 38677}

46_{Université de Montréal, Laboratoire Rene J. A. Levesque, Montréal, Canada QC H3C 3J7} 47_{Mount Holyoke College, South Hadley, Massachusetts 01075}

48_{Università di Napoli Federico II, Dipartimento di Scienze Fisiche and INFN, I-80126, Napoli, Italy} 49_{University of Notre Dame, Notre Dame, Indiana 46556}

50_{Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831} 51_{University of Oregon, Eugene, Oregon 97403}

52_{Università di Padova, Dipartimento di Fisica and INFN, I-35131 Padova, Italy} 53_{Universités Paris VI et VII, LPNHE, F-75252 Paris, France}

54_{Università di Pavia, Dipartimento di Elettronica and INFN, I-27100 Pavia, Italy} 55_{University of Pennsylvania, Philadelphia, Pennsylvania 19104}

56_{Università di Pisa, Scuola Normale Superiore and INFN, I-56010 Pisa, Italy} 57_{Prairie View A&M University, Prairie View, Texas 77446}

58_{Princeton University, Princeton, New Jersey 08544}

59_{Università di Roma La Sapienza, Dipartimento di Fisica and INFN, I-00185 Roma, Italy} 60_{Universität Rostock, D-18051 Rostock, Germany}

61_{Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, United Kingdom} 62_{DAPNIA, Commissariat à l’Energie Atomique/Saclay, F-91191 Gif-sur-Yvette, France}

63_{University of South Carolina, Columbia, South Carolina 29208} 64_{Stanford Linear Accelerator Center, Stanford, California 94309}

65_{Stanford University, Stanford, California 94305-4060} 66_{TRIUMF, Vancouver, British Columbia Canada V6T 2A3}

67_{University of Tennessee, Knoxville, Tennessee 37996} 68_{University of Texas at Dallas, Richardson, Texas 75083}

69_{Università di Torino, Dipartimento di Fiscia Sperimentale and INFN, I-10125 Torino, Italy} 70_{Università di Trieste, Dipartimento di Fisica and INFN, I-34127 Trieste, Italy}

71_{Vanderbilt University, Nashville, Tennessee 37235}

72_{University of Victoria, Victoria, British Columbia Canada V8W 3P6} 73_{University of Wisconsin, Madison, Wisconsin 53706}

74_{Yale University, New Haven, Connecticut 06511}

(Received 7 August 2001; published 12 November 2001)

We present the results of searches for B decays to charmless two-body final states containing h0

or v mesons, based on 20.7fb21 of data collected with the BABAR detector. We find the branch-ing fractions B共B1_!h0_K1_{兲苷共706865兲310}26_{, B共B}0_!h0_K0_兲苷共42113

211 64兲31026, and

B_共B1 !vp1_兲苷共6.612.1

21.860.7兲31026, where the first error quoted is statistical and the second

is systematic. We give measurements of four additional modes for which the 90% confidence level upper limits are B_共B1 _!h0_p1_兲,1231026_{, B共B}1_!vK1_兲,431026_{, B共B}0 _!vK0_兲, 1331026_{, andB共B}0_!vp0_兲,331026_.

We report results of searches forBdecays to the charm-less two-body final states [1] B1 _!vp1_{, B}1 _{! vK}1_, B1 _!h0_p1_{, B}1 _!h0_K1_{, B}0_{! vK}0_{, B}0 _!vp0_, and B0 _!h0_K0_{. These processes are manifestations} of penguin or suppressed tree amplitudes proportional to small couplings in hadronic flavor mixing [Cabibbo-Kobayashi-Maskawa (CKM) matrix [2] ]. Because of the absence of CKM favoredb !camplitudes, these decays are particularly sensitive to potentially new contributions from interference effects and virtual particles in loops. Previous measurements [3] yielded an unexpectedly large rate for B!h0K, motivating a number of new theoretical ideas. The precise measurement of these and additional rareBdecay modes will enable a better under-standing of the underlying decay mechanism, including the possible contribution of physics beyond the standard model. This in turn will contribute to the measurement of fundamental parameters, including the CP-violating CKM phases.

The data were collected with the BABAR detector [4] at the PEP-II asymmetrice1e2 collider [5] located at the Stanford Linear Accelerator Center. The results presented in this paper are based on data taken in the 1999–2000 run. An integrated luminosity of20.7fb21_{, corresponding} to 22.7 millionBBpairs, was recorded at theY共4S兲 reso-nance (“on resoreso-nance,” 10.58GeV), with an additional 2.6fb21 _{about 40MeV below this energy (“off} reso-nance”) for the study of continuum backgrounds.

The asymmetric beam configuration in the laboratory frame provides a boost to theY共4S兲increasing the momen-tum range of theBmeson decay products up to4.3GeV兾c. Charged particles are detected and their momenta are mea-sured by a combination of a silicon vertex tracker, consist-ing of five layers of double-sided detectors, and a 40-layer central drift chamber, both operating in the1.5T magnetic field of a solenoid. Photons and electrons are detected by a CsI(Tl) electromagnetic calorimeter (EMC), which pro-vides excellent angular and energy resolution with high efficiency for energies above 20MeV [4].

Charged particle identification (PID) is provided by the average energy loss 共dE兾dx兲 in the tracking devices and by a unique, ring imaging detector of internally reflecting Cherenkov (DIRC) light covering the central region. A Cherenkov angle K 2 p separation of better than four standard deviations 共s兲 is achieved for tracks below 3GeV兾c momentum, decreasing to 2.5s at the highest momenta in the final states considered here [6]. Electrons are identified with the use of the EMC.

We reconstruct aB meson candidate by combining an v or h0 candidate with a charged track, p0 !gg, or KS0! p1p2. The resonance decaysRwe reconstruct are

v !p1_p2_p0_{, h}0 _!hp1_p2 _共h0

hpp兲, or h0 !r0g 共h_rg0 兲, with h ! gg and r0! p1p2. These modes are kinematically distinct from the dominant B decays to heavier charmed states. Backgrounds come primarily from combinatorics among continuum events in which a light quark pair is produced instead of anY共4S兲.

Monte Carlo (MC) simulations [7] of the target decay modes and of continuum background are used to establish the event selection criteria. The selection is designed to achieve high efficiency and retain sidebands sufficient to characterize the background for subsequent fitting. Pho-tons must satisfyEg . 50共100兲 MeV for p0 _共h兲 candi-dates. For h0 ! r0g candidates fromB1 !h0K1 and B1 ! h0p1 the requirement is Eg .200MeV, while for B0 !h0K0 it is looser (Eg . 100MeV) because of smaller combinatoric background.

We select v, h0, h, and r candidates with the fol-lowing requirements on the invariant masses in MeV兾c2 of their final states: 735, m共p1_p2_p0_{兲, 830, 930,} m共hp1_p2_{兲, 990, 900,m共rg兲, 1000, 490,} m共gg兲, 600, and 500,m共p1_p2_{兲, 995. For p}0 andKS0 candidates we require 120,m共gg兲 ,150 and

488,m共p1_p2_兲,508.

Tracks in v, h0, or r candidates must have DIRC, dE兾dx, and EMC responses consistent with pions. For chargedBdecays, theBprimary track must have an asso-ciated DIRC Cherenkov angle within3.5sof the expected value for a kaon or pion. For modes with KS0 the

three-dimensional flight distance from the production point must exceed2mm, and the angle between the flight and momentum vectors projected perpendicular to the beam must be less than 40mrad.

A B meson candidate is characterized by two kine-matic observables. The minimally correlated pair we use is the energy constrained mass mEC and energy differ-ence DE. In the Y共4S兲 frame the B meson energy Eⴱ equals the beam energyEⴱbeam. A kinematic fit of the mea-sured candidate four momentum in this frame with the con-straintEⴱ 苷Ebeamⴱ yieldsmEC, whileDE ⬅Eⴱ 2Ebeamⴱ measures the consistency of this constraint. We require jDEj#0.2GeV and mEC $5.2GeV兾c2. The resolu-tions on these quantities are mode dependent but average about30MeV and2.8MeV兾c2_{, respectively.}

To discriminate against tau-pair and two-photon back-ground we require the event to contain at least five charged tracks. To reject continuum background we make use of the angle uT between the thrust axes of the B candidate

and the rest of the tracks and neutral clusters in the event, calculated in the center-of-mass frame. The distribution of cosuT is sharply peaked near61for combinations drawn

from jetlikeqqpairs, and nearly uniform for the isotropic Bmeson decays.

are in very good agreement. Simple cut-based analyses are performed as checks for each final state. Agreement of central values is good in all cases, although, as expected, errors are larger than for the ML analyses, particularly for modes having high background.

The ML1 fit method is applied to events satisfying jcosuTj#0.9. The input observables are DE, mEC, the

invariant massmRof the intermediate resonance, the Fisher

discriminantF, and, where relevant, thehmass mh, the measured DIRC angle for theBprimary track, and the co-sineH of the helicity angle, the angle in thevrest frame between the normal to thev decay plane and theBflight direction. The Fisher discriminant [8] combines eleven variables: the angles with respect to the beam axis in the Y共4S兲 frame of the B momentum and the B two-body decay axis, and a nine bin representation of the energy flow about theB decay axis.

For the ML2 method we relax the preliminary require-ments to 100, m共gg兲, 160MeV兾c2 _{and jDEj,} 0.3GeV. The neural network is constructed with the B momentum pⴱ, ax2 for resonance masses,H, and vari-ables representing energy flow and angular distributions, including uT.

We use MC to estimate backgrounds from otherB de-cays, including final states with and without charm. For most of our modes we find contributions that are negli-gible. For theh0 !r0_{gmodes we account for small cross} feed contributions in the systematic error estimate.

The likelihood function forN events is

L 苷 e 2共Pnj兲

N!

N

Y

i苷1

L_i, L_i 苷

m

X

j苷1

njPj共xi兲.

Here nj is the population size for species j (e.g., signal,

background) and P_j共xi兲 is the corresponding probability distribution function (PDF), evaluated with the observables

xi of the ith event.

For the fits of chargedBdecays,L_i becomes L_i 苷npPpS共xi兲1nKPKS共xi兲

1nC关fKCPKC共xi兲 1共12fKC兲PpC共xi兲兴,

where np共nK兲 is the number of B1 !Rp1 共B1 !

RK1兲 signal events, nC is the number of continuum

background events, and fKC is the fraction of continuum

background events for which theBprimary track is iden-tified as a kaon. These quantities are the free parameters of the ML fit. The probabilities for the components are PpS 共PKS兲 for B1 ! Rp1 共B1 ! RK1兲 signal and

P_pC 共P_KC兲 for background where the primary track is a pion (kaon). Since we measure the correlations among the observables in the data to be small, we take eachP_jto be a product of the PDFs for the separate observables. The analyses involving aKS0are treated identically, except that

there is only one component of signal and of continuum background.

A second B candidate satisfying the preliminary cuts occurs in about 10% 20%of the events. In this case the

“best” combination is selected according to ax2_quantity computed withmEC,mR,mh(forh0 ! hp1p2modes), and the Fisher discriminant.

We determine the PDFs for the likelihood fits from simulation for the signal component, and from off-resonance and sideband data for the continuum back-ground. Peaking distributions (signal masses, DE, F) are parametrized as Gaussians, with or without a second Gaussian or asymmetric width as required to describe the distributions. Slowly varying distributions (combinatoric background under mass or energy peaks, H orF) have first or second order polynomial shapes. The combinatoric background in mEC is described by a phase space moti-vated empirical function [9]. Control samples ofBdecays to charmed final states of similar topology are used to verify the simulated resolutions inDEandmEC. Inclusive resonance production samples, such as those shown in Fig. 1, are used similarly for the relevantBdaughter mass spectra.

We compute the branching fractions from the fitted signal event yields, reconstruction efficiency, daughter branching fractions, and the number of produced B mesons, assuming equal production rates of charged and neutral pairs. To determine the reconstruction efficiency, including any yield bias of the likelihood fit, we apply the method to simulated samples with the signal and continuum background populations expected in the data. Table I shows for each decay chain the branching fraction we measure, together with the quantities entering into its computation. The statistical error on the number of events is taken as the shift from the central value that changes the quantityx2 _{⬅22log共L兾Lmax兲by one unit. We also} give the significance S, computed as the square root of the difference between the value ofx2_{for zero signal and} the value at its minimum. The x2 _{used for significance} includes a term that accounts for the additive systematic

930.0 950.0 970.0 990.0 mass(π+π−η) 0 1 2 3 4 5 Events/MeV/c 2 (a) x1000 x1000

742.0 782.0 822.0 mass(π+π−π0) (MeV/c2) 50 60 70 80 90 (b)

FIG. 1. Invariant mass distributions for inclusive data samples of candidates with Y共4S兲 frame momentum greater than

2.3GeV兾cfor (a)h0, with520,m共gg兲,575MeV兾c2_{, and}

(b) v candidates, with 120,m共gg兲,150MeV兾c2_{. From}

the overlaid fit curves, the Gaussian peak widths are 4 and

TABLE I. Signal event yield with statistical uncertainty, detection efficiency e, daughter branching fractions that were forced to 100% in our signal mode simulations, significance

S (defined in the text), and branching fraction result for each decay chain or mode, with the final (combined) result given in bold type. We show90%confidence upper limits in parentheses where appropriate.

e QB_i S B

Mode Yield (%) (%) (s) (1026₎

h0

hppK1 49.5 18.1

27.3 20 17.4 15 6312109

h0rgK1 87.6 113.4

212.5 18 29.5 11 80121211

h0K1 · · · 17 706865

h0_hppK0 _6.313.3

22.5 16 6.0 4.7 28121511

h_rg0 K0 20.8216.57.4 16 10.1 4.2 61122219

h0K0 _{· · · · · · · · · 5.9 42}113

211 64

h0_hppp1 _5.713.8

22.8 20 17.4 3.2 7.1

14.8 23.5

h0rgp1 20.9 17.8

26.2 19 29.5 0.1 20.7126.75.3

h0p1 _{· · · · · · · · · 2.8 5.4}13.5

22.660.8共,12兲

vK1 _6.415.6

24.4 22 88.8 1.3 1.42111..3060.3共,4兲

vK0 _8.114.6

23.6 18 30.5 3.2 6.42132..6860.8共,13兲

vp1 27.6128.87.7 21 88.8 4.9 6.61221..1860.7

vp0 _20.915.0

23.2 18 88.8 · · · 20.361.160.3共,3兲

error discussed below. Where the significance is less than four standard deviations, we quote also (Bayesian) 90%C.L. upper limits, defined by the solution B to the conditionRB₀L共b兲db兾R`₀L共b兲db 苷 0.9.

In Fig. 2 we show projections ofmEC and DE for the modes with significant yields. The projections are made by

0 25 50

(a)

0 10 20 30

(b)

0 8

Events/2 MeV/c

2

(c)

0 2 4

Events/8 MeV

(d)

5.20 5.25 5.30

m_EC (GeV/c2)

0 4 8

(e)

-0.16 0.00 0.16

∆E (GeV)

0 4 8

(f)

FIG. 2. B candidate mEC and DE for B1 !h0K1 (a),(b), B0_!h0_K0 _{(c),(d), andB}1 _!vp1 _{(e),(f ). Histograms}

repre-sent data, with the h0_{!hpp subset shaded, the solid curves}

represent the full fit functions, and the dashed curves represent the background functions.

selecting events with signal likelihood (computed without the variable plotted) exceeding a mode-dependent thresh-old that optimizes the expected sensitivity.

We have evaluated systematic errors, which are domi-nated in most cases by the PDF uncertainties (3% 18%, depending on the decay mode). To determine these we vary parameters of the PDFs within their uncertainties and observe the impact on the fit yield. We include them in up-per limits by convolution with the likelihood function. This is the only additive systematic error; all others are multi-plicative. The estimate of any systematic bias from the fit-ter itself (1% 4%) comes from fits of simulated samples with varying background populations.

The uncertainty in our knowledge of the efficiency is found from auxiliary studies to be 1% per track, 1.25% per photon, and 5% per KS0 for the candidate B and the

unreconstructedB, which must contribute tracks to fulfill the event multiplicity requirement. We add these errors linearly for the required tracks in the event and, similarly, for the photons and neutral kaons. Our estimate of the B production systematic error is 1.6%. Published world averages [10] provide the B daughter branching fraction uncertainties.

Systematic errors associated with the event selection are minimal given the generally loose requirements. We ac-count explicitly for cosuT (1%), for which we observe a

nearly uniform distribution in the signal simulation. We also include errors of 4% from those PID requirements that are imposed via cuts rather than the fit.

by adding thex2_{distributions that represent them and their} uncorrelated statistical and systematic errors.

The final results are generally in agreement with those previously reported [3,11], with somewhat smaller errors. In particular, we confirm the expectedB共B1 !vp1兲 . B共B1 !vK1兲, and the rather larger than predicted [12] rate for B !h0K obtained by the CLEO Collaboration [3]. Conjectured sources ofh0enhancement include flavor singlet [13], charm enhanced [14], and constructively in-terfering internal penguin diagrams [12,15]. Our results in combination with expected measurements of related modes involvinghandKⴱshould help to clarify this situation.

We are grateful for the excellent luminosity and machine conditions provided by our PEP-II colleagues. The col-laborating institutions wish to thank SLAC for its support and kind hospitality. This work is supported by DOE and NSF (U.S.A.), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF (Germany), INFN (Italy), NFR (Norway), MIST (Russia), and PPARC (United King-dom). Individuals have received support from the Swiss NSF, A. P. Sloan Foundation, Research Corporation, and Alexander von Humboldt Foundation.

*Also with Università di Perugia, Perugia, Italy.

†_{Also with Università della Basilicata, Potenza, Italy.}

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GEANT; R. Brun et al.,CERN Report No. DD/EE/84-1. [8] CLEO Collaboration, D. M. Asneret al.,Phys. Rev. D53,

1039 (1996).

[9] With x⬅mEC兾Eb and j a parameter to be fit, f共x兲~ xp12x2_{exp关2j共12x}2_{兲兴. See ARGUS Collaboration,}

H. Albrechtet al.,Phys. Lett. B241,278 (1990). [10] Particle Data Group, D. E. Groomet al., Eur. Phys. J. C

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