Determinations of |Vub| from Inclusive Semileptonic B Decays with Reduced Model Dependence

arXiv:hep-ex/0601046v2 25 May 2006

SLAC-PUB-11582 hep-ex/0601046

Determinations of

_|V

| from Inclusive Semileptonic B Decays with Reduced Model

Dependence

B. Aubert,1 _{R. Barate,}1_{D. Boutigny,}1 _{F. Couderc,}1 _{Y. Karyotakis,}1 _{J. P. Lees,}1 _{V. Poireau,}1 _{V. Tisserand,}1

A. Zghiche,1 _{E. Grauges,}2 _{A. Palano,}3 _{M. Pappagallo,}3_{A. Pompili,}3 _{J. C. Chen,}4 _{N. D. Qi,}4 _{G. Rong,}4

P. Wang,4_{Y. S. Zhu,}4 _{G. Eigen,}5_{I. Ofte,}5 _{B. Stugu,}5 _{G. S. Abrams,}6_{M. Battaglia,}6_{D. S. Best,}6 _{D. N. Brown,}6

J. Button-Shafer,6 _{R. N. Cahn,}6 _{E. Charles,}6 _{C. T. Day,}6 _{M. S. Gill,}6 _{A. V. Gritsan,}6, ∗ _{Y. Groysman,}6

R. G. Jacobsen,6_{R. W. Kadel,}6 _{J. A. Kadyk,}6_{L. T. Kerth,}6 _{Yu. G. Kolomensky,}6 _{G. Kukartsev,}6 _{G. Lynch,}6

L. M. Mir,6 _{P. J. Oddone,}6_{T. J. Orimoto,}6 _{M. Pripstein,}6 _{N. A. Roe,}6 _{M. T. Ronan,}6_{W. A. Wenzel,}6 _{M. Barrett,}7

K. E. Ford,7 _{T. J. Harrison,}7 _{A. J. Hart,}7 _{C. M. Hawkes,}7 _{S. E. Morgan,}7_{A. T. Watson,}7_{M. Fritsch,}8 _{K. Goetzen,}8

T. Held,8 _{H. Koch,}8 _{B. Lewandowski,}8 _{M. Pelizaeus,}8 _{K. Peters,}8 _{T. Schroeder,}8 _{M. Steinke,}8 _{J. T. Boyd,}9

J. P. Burke,9 _{W. N. Cottingham,}9 _{D. Walker,}9 _{T. Cuhadar-Donszelmann,}10_{B. G. Fulsom,}10 _{C. Hearty,}10

N. S. Knecht,10_{T. S. Mattison,}10 _{J. A. McKenna,}10_{A. Khan,}11 _{P. Kyberd,}11 _{M. Saleem,}11 _{L. Teodorescu,}11

A. E. Blinov,12 _{V. E. Blinov,}12 _{A. D. Bukin,}12 _{V. P. Druzhinin,}12 _{V. B. Golubev,}12 _{E. A. Kravchenko,}12

A. P. Onuchin,12_{S. I. Serednyakov,}12_{Yu. I. Skovpen,}12_{E. P. Solodov,}12 _{A. N. Yushkov,}12 _{M. Bondioli,}13

M. Bruinsma,13_{M. Chao,}13_{S. Curry,}13_{I. Eschrich,}13 _{D. Kirkby,}13_{A. J. Lankford,}13 _{P. Lund,}13 _{M. Mandelkern,}13

R. K. Mommsen,13 _{W. Roethel,}13 _{D. P. Stoker,}13 _{S. Abachi,}14 _{C. Buchanan,}14_{S. D. Foulkes,}15 _{J. W. Gary,}15

O. Long,15 _{B. C. Shen,}15 _{K. Wang,}15 _{L. Zhang,}15 _{D. del Re,}16_{H. K. Hadavand,}16_{E. J. Hill,}16 _{D. B. MacFarlane,}16

H. P. Paar,16_{S. Rahatlou,}16 _{V. Sharma,}16 _{J. W. Berryhill,}17_{C. Campagnari,}17 _{A. Cunha,}17 _{B. Dahmes,}17

T. M. Hong,17 _{M. A. Mazur,}17 _{J. D. Richman,}17 _{T. W. Beck,}18 _{A. M. Eisner,}18 _{C. J. Flacco,}18 _{C. A. Heusch,}18

J. Kroseberg,18 _{W. S. Lockman,}18 _{G. Nesom,}18 _{T. Schalk,}18 _{B. A. Schumm,}18 _{A. Seiden,}18 _{P. Spradlin,}18

D. C. Williams,18 _{M. G. Wilson,}18 _{J. Albert,}19_{E. Chen,}19_{G. P. Dubois-Felsmann,}19_{A. Dvoretskii,}19 _{D. G. Hitlin,}19

J. S. Minamora,19 _{I. Narsky,}19 _{T. Piatenko,}19 _{F. C. Porter,}19 _{A. Ryd,}19 _{A. Samuel,}19 _{R. Andreassen,}20

G. Mancinelli,20 _{B. T. Meadows,}20_{M. D. Sokoloff,}20 _{F. Blanc,}21 _{P. C. Bloom,}21 _{S. Chen,}21 _{W. T. Ford,}21

J. F. Hirschauer,21 _{A. Kreisel,}21_{U. Nauenberg,}21 _{A. Olivas,}21 _{W. O. Ruddick,}21 _{J. G. Smith,}21 _{K. A. Ulmer,}21

S. R. Wagner,21_{J. Zhang,}21_{A. Chen,}22_{E. A. Eckhart,}22_{A. Soffer,}22_{W. H. Toki,}22_{R. J. Wilson,}22_{F. Winklmeier,}22

Q. Zeng,22 _{D. D. Altenburg,}23 _{E. Feltresi,}23 _{A. Hauke,}23 _{B. Spaan,}23 _{T. Brandt,}24 _{M. Dickopp,}24 _{V. Klose,}24

H. M. Lacker,24 _{R. Nogowski,}24_{S. Otto,}24 _{A. Petzold,}24 _{J. Schubert,}24 _{K. R. Schubert,}24 _{R. Schwierz,}24

J. E. Sundermann,24 _{D. Bernard,}25_{G. R. Bonneaud,}25 _{P. Grenier,}25, † _{E. Latour,}25 _{S. Schrenk,}25 _{Ch. Thiebaux,}25

G. Vasileiadis,25_{M. Verderi,}25 _{D. J. Bard,}26 _{P. J. Clark,}26 _{W. Gradl,}26 _{F. Muheim,}26 _{S. Playfer,}26 _{Y. Xie,}26

M. Andreotti,27 _{D. Bettoni,}27 _{C. Bozzi,}27 _{R. Calabrese,}27 _{G. Cibinetto,}27 _{E. Luppi,}27 _{M. Negrini,}27

L. Piemontese,27_{F. Anulli,}28 _{R. Baldini-Ferroli,}28_{A. Calcaterra,}28_{R. de Sangro,}28 _{G. Finocchiaro,}28 _{P. Patteri,}28

I. M. Peruzzi,28, ‡_{M. Piccolo,}28 _{A. Zallo,}28 _{A. Buzzo,}29 _{R. Capra,}29 _{R. Contri,}29 _{M. Lo Vetere,}29 _{M. M. Macri,}29

M. R. Monge,29_{S. Passaggio,}29_{C. Patrignani,}29_{E. Robutti,}29 _{A. Santroni,}29 _{S. Tosi,}29 _{G. Brandenburg,}30

K. S. Chaisanguanthum,30_{M. Morii,}30 _{J. Wu,}30 _{R. S. Dubitzky,}31 _{U. Langenegger,}31, § _{J. Marks,}31_{S. Schenk,}31

U. Uwer,31 _{W. Bhimji,}32 _{D. A. Bowerman,}32 _{P. D. Dauncey,}32_{U. Egede,}32_{R. L. Flack,}32 _{J. R. Gaillard,}32 _J

.A. Nash,32 _{M. B. Nikolich,}32 _{W. Panduro Vazquez,}32 _{X. Chai,}33 _{M. J. Charles,}33 _{W. F. Mader,}33 _{U. Mallik,}33

V. Ziegler,33_{J. Cochran,}34 _{H. B. Crawley,}34_{L. Dong,}34_{V. Eyges,}34 _{W. T. Meyer,}34_{S. Prell,}34 _{E. I. Rosenberg,}34

A. E. Rubin,34 _{J. I. Yi,}34 _{G. Schott,}35_{N. Arnaud,}36 _{M. Davier,}36 _{X. Giroux,}36_{G. Grosdidier,}36_{A. H¨ocker,}36 _{F. Le}

Diberder,36_{V. Lepeltier,}36 _{A. M. Lutz,}36_{A. Oyanguren,}36_{T. C. Petersen,}36_{S. Pruvot,}36_{S. Rodier,}36_{P. Roudeau,}36

M. H. Schune,36 _{A. Stocchi,}36 _{W. F. Wang,}36 _{G. Wormser,}36_{C. H. Cheng,}37 _{D. J. Lange,}37 _{D. M. Wright,}37

A. J. Bevan,38 _{C. A. Chavez,}38 _{I. J. Forster,}38 _{J. R. Fry,}38 _{E. Gabathuler,}38 _{R. Gamet,}38 _{K. A. George,}38

D. E. Hutchcroft,38 _{R. J. Parry,}38 _{D. J. Payne,}38 _{K. C. Schofield,}38 _{C. Touramanis,}38 _{F. Di Lodovico,}39

W. Menges,39 _{R. Sacco,}39 _{C. L. Brown,}40 _{G. Cowan,}40 _{H. U. Flaecher,}40 _{M. G. Green,}40 _{D. A. Hopkins,}40

P. S. Jackson,40 _{T. R. McMahon,}40 _{S. Ricciardi,}40 _{F. Salvatore,}40 _{D. N. Brown,}41 _{C. L. Davis,}41_{J. Allison,}42

N. R. Barlow,42 _{R. J. Barlow,}42_{Y. M. Chia,}42_{C. L. Edgar,}42_{M. P. Kelly,}42 _{G. D. Lafferty,}42 _{M. T. Naisbit,}42

J. C. Williams,42 C. Chen,43 W. D. Hulsbergen,43 A. Jawahery,43 D. Kovalskyi,43 C. K. Lae,43 D. A. Roberts,43 G. Simi,43 _{G. Blaylock,}44 _{C. Dallapiccola,}44 _{S. S. Hertzbach,}44 _{R. Kofler,}44 _{X. Li,}44 _{T. B. Moore,}44_{S. Saremi,}44

H. Staengle,44 _{S. Y. Willocq,}44 _{R. Cowan,}45 _{K. Koeneke,}45_{G. Sciolla,}45_{S. J. Sekula,}45 _{M. Spitznagel,}45

F. Taylor,45 _{R. K. Yamamoto,}45 _{H. Kim,}46 _{P. M. Patel,}46_{S. H. Robertson,}46 _{A. Lazzaro,}47 _{V. Lombardo,}47

F. F. Palombo,47 _{J. M. Bauer,}48 _{L. Cremaldi,}48 _{V. Eschenburg,}48 _{R. Godang,}48 _{R. Kroeger,}48_{J. Reidy,}48

D. A. Sanders,48_{D. J. Summers,}48_{H. W. Zhao,}48_{S. Brunet,}49_{D. Cˆot´e,}49_{P. Taras,}49_{F. B. Viaud,}49_{H. Nicholson,}50

N. Cavallo,51, ¶ _{G. De Nardo,}51 _{F. Fabozzi,}51, ¶ _{C. Gatto,}51_{L. Lista,}51_{D. Monorchio,}51 _{P. Paolucci,}51_{D. Piccolo,}51

C. Sciacca,51_{M. Baak,}52 _{H. Bulten,}52 _{G. Raven,}52_{H. L. Snoek,}52_{L. Wilden,}52 _{C. P. Jessop,}53 _{J. M. LoSecco,}53

T. Allmendinger,54 _{G. Benelli,}54 _{K. K. Gan,}54_{K. Honscheid,}54 _{D. Hufnagel,}54 _{P. D. Jackson,}54_{H. Kagan,}54

R. Kass,54_{T. Pulliam,}54 _{A. M. Rahimi,}54 _{R. Ter-Antonyan,}54_{Q. K. Wong,}54 _{N. L. Blount,}55 _{J. Brau,}55 _{R. Frey,}55

O. Igonkina,55 _{M. Lu,}55_{C. T. Potter,}55_{R. Rahmat,}55 _{N. B. Sinev,}55 _{D. Strom,}55 _{J. Strube,}55 _{E. Torrence,}55

F. Galeazzi,56 _{M. Margoni,}56 _{M. Morandin,}56 _{M. Posocco,}56 _{M. Rotondo,}56 _{F. Simonetto,}56 _{R. Stroili,}56

C. Voci,56 _{M. Benayoun,}57 _{J. Chauveau,}57 _{P. David,}57 _{L. Del Buono,}57 _{Ch. de la Vaissi`ere,}57_{O. Hamon,}57

B. L. Hartfiel,57 M. J. J. John,57Ph. Leruste,57J. Malcl`es,57 J. Ocariz,57 L. Roos,57 G. Therin,57 P. K. Behera,58 L. Gladney,58 _{J. Panetta,}58 _{M. Biasini,}59 _{R. Covarelli,}59 _{S. Pacetti,}59_{M. Pioppi,}59 _{C. Angelini,}60 _{G. Batignani,}60

S. Bettarini,60 _{F. Bucci,}60 _{G. Calderini,}60_{M. Carpinelli,}60_{R. Cenci,}60 _{F. Forti,}60 _{M. A. Giorgi,}60_{A. Lusiani,}60

G. Marchiori,60_{M. Morganti,}60_{N. Neri,}60 _{E. Paoloni,}60 _{M. Rama,}60 _{G. Rizzo,}60 _{J. Walsh,}60 _{M. Haire,}61

D. Judd,61 _{D. E. Wagoner,}61 _{J. Biesiada,}62 _{N. Danielson,}62 _{P. Elmer,}62 _{Y. P. Lau,}62 _{C. Lu,}62 _{J. Olsen,}62

A. J. S. Smith,62 _{A. V. Telnov,}62 _{F. Bellini,}63 _{G. Cavoto,}63_{A. D’Orazio,}63 _{E. Di Marco,}63 _{R. Faccini,}63

F. Ferrarotto,63 _{F. Ferroni,}63 _{M. Gaspero,}63_{L. Li Gioi,}63 _{M. A. Mazzoni,}63_{S. Morganti,}63 _{G. Piredda,}63

F. Polci,63_{F. Safai Tehrani,}63 _{C. Voena,}63_{H. Schr¨oder,}64 _{R. Waldi,}64 _{T. Adye,}65 _{N. De Groot,}65 _{B. Franek,}65

G. P. Gopal,65 _{E. O. Olaiya,}65 _{F. F. Wilson,}65 _{R. Aleksan,}66 _{S. Emery,}66 _{A. Gaidot,}66 _{S. F. Ganzhur,}66

G. Graziani,66 _{G. Hamel de Monchenault,}66 _{W. Kozanecki,}66_{M. Legendre,}66 _{B. Mayer,}66 _{G. Vasseur,}66

Ch. Y`eche,66 _{M. Zito,}66_{M. V. Purohit,}67_{A. W. Weidemann,}67_{J. R. Wilson,}67_{T. Abe,}68 _{M. T. Allen,}68_{D. Aston,}68

R. Bartoldus,68_{N. Berger,}68 _{A. M. Boyarski,}68_{O. L. Buchmueller,}68_{R. Claus,}68 _{J. P. Coleman,}68 _{M. R. Convery,}68

M. Cristinziani,68 _{J. C. Dingfelder,}68 _{D. Dong,}68 _{J. Dorfan,}68 _{D. Dujmic,}68 _{W. Dunwoodie,}68 _{S. Fan,}68

R. C. Field,68 _{T. Glanzman,}68 _{S. J. Gowdy,}68 _{T. Hadig,}68_{V. Halyo,}68 _{C. Hast,}68 _{T. Hryn’ova,}68 _{W. R. Innes,}68

M. H. Kelsey,68_{P. Kim,}68 _{M. L. Kocian,}68 _{D. W. G. S. Leith,}68 _{J. Libby,}68 _{S. Luitz,}68 _{V. Luth,}68 _{H. L. Lynch,}68

H. Marsiske,68_{R. Messner,}68 _{D. R. Muller,}68 _{C. P. O’Grady,}68 _{V. E. Ozcan,}68 _{A. Perazzo,}68_{M. Perl,}68

B. N. Ratcliff,68 _{A. Roodman,}68 _{A. A. Salnikov,}68_{R. H. Schindler,}68_{J. Schwiening,}68_{A. Snyder,}68 _{J. Stelzer,}68

D. Su,68 _{M. K. Sullivan,}68_{K. Suzuki,}68 _{S. K. Swain,}68 _{J. M. Thompson,}68_{J. Va’vra,}68_{N. van Bakel,}68_{M. Weaver,}68

A. J. R. Weinstein,68 _{W. J. Wisniewski,}68_{M. Wittgen,}68 _{D. H. Wright,}68 _{A. K. Yarritu,}68_{K. Yi,}68_{C. C. Young,}68

P. R. Burchat,69 _{A. J. Edwards,}69 _{S. A. Majewski,}69 _{B. A. Petersen,}69 _{C. Roat,}69 _{S. Ahmed,}70 _{M. S. Alam,}70

R. Bula,70 _{J. A. Ernst,}70 _{B. Pan,}70 _{M. A. Saeed,}70 _{F. R. Wappler,}70 _{S. B. Zain,}70 _{W. Bugg,}71 _{M. Krishnamurthy,}71

S. M. Spanier,71_{R. Eckmann,}72 _{J. L. Ritchie,}72_{A. Satpathy,}72 _{R. F. Schwitters,}72_{J. M. Izen,}73_{I. Kitayama,}73

X. C. Lou,73 _{S. Ye,}73 _{F. Bianchi,}74 _{M. Bona,}74_{F. Gallo,}74_{D. Gamba,}74 _{M. Bomben,}75 _{L. Bosisio,}75_{C. Cartaro,}75

F. Cossutti,75 _{G. Della Ricca,}75 _{S. Dittongo,}75 _{S. Grancagnolo,}75_{L. Lanceri,}75_{L. Vitale,}75 _{V. Azzolini,}76

F. Martinez-Vidal,76 _{R. S. Panvini,}77, ∗∗ _{Sw. Banerjee,}78 _{B. Bhuyan,}78_{C. M. Brown,}78 _{D. Fortin,}78_{K. Hamano,}78

R. Kowalewski,78 _{I. M. Nugent,}78 _{J. M. Roney,}78 _{R. J. Sobie,}78 _{J. J. Back,}79 _{P. F. Harrison,}79_{T. E. Latham,}79

G. B. Mohanty,79 _{H. R. Band,}80 _{X. Chen,}80 _{B. Cheng,}80 _{S. Dasu,}80 _{M. Datta,}80 _{A. M. Eichenbaum,}80

K. T. Flood,80 _{M. T. Graham,}80_{J. J. Hollar,}80_{J. R. Johnson,}80 _{P. E. Kutter,}80 _{H. Li,}80_{R. Liu,}80_{B. Mellado,}80

A. Mihalyi,80_{A. K. Mohapatra,}80_{Y. Pan,}80_{M. Pierini,}80_{R. Prepost,}80 _{P. Tan,}80_{S. L. Wu,}80_{Z. Yu,}80_{and H. Neal}81

(The BA_BAR _{Collaboration)}

1_{Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France} 2_{IFAE, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain}

3_{Universit`a di Bari, Dipartimento di Fisica and INFN, I-70126 Bari, Italy} 4_{Institute of High Energy Physics, Beijing 100039, China}

5_{University of Bergen, Institute of Physics, N-5007 Bergen, Norway}

6_{Lawrence Berkeley National Laboratory and University of California, Berkeley, California 94720, USA} 7_{University of Birmingham, Birmingham, B15 2TT, United Kingdom}

8_{Ruhr Universit¨at Bochum, Institut f¨ur Experimentalphysik 1, D-44780 Bochum, Germany} 9_{University of Bristol, Bristol BS8 1TL, United Kingdom}

10_{University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1} 11_{Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom}

12_{Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia} 13_{University of California at Irvine, Irvine, California 92697, USA}

14_{University of California at Los Angeles, Los Angeles, California 90024, USA} 15_{University of California at Riverside, Riverside, California 92521, USA} 16_{University of California at San Diego, La Jolla, California 92093, USA} 17_{University of California at Santa Barbara, Santa Barbara, California 93106, USA}

18_{University of California at Santa Cruz, Institute for Particle Physics, Santa Cruz, California 95064, USA} 19_{California Institute of Technology, Pasadena, California 91125, USA}

20_{University of Cincinnati, Cincinnati, Ohio 45221, USA} 21_{University of Colorado, Boulder, Colorado 80309, USA} 22_{Colorado State University, Fort Collins, Colorado 80523, USA} 23_{Universit¨at Dortmund, Institut f¨ur Physik, D-44221 Dortmund, Germany}

24_{Technische Universit¨at Dresden, Institut f¨ur Kern- und Teilchenphysik, D-01062 Dresden, Germany} 25_{Ecole Polytechnique, LLR, F-91128 Palaiseau, France}

26_{University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom}

27_{Universit`a di Ferrara, Dipartimento di Fisica and INFN, I-44100 Ferrara, Italy</sub> 28<sub>Laboratori Nazionali di Frascati dell’INFN, I-00044 Frascati, Italy</sub> 29<sub>Universit`a di Genova, Dipartimento di Fisica and INFN, I-16146 Genova, Italy}

30_{Harvard University, Cambridge, Massachusetts 02138, USA}

31_{Universit¨at Heidelberg, Physikalisches Institut, Philosophenweg 12, D-69120 Heidelberg, Germany} 32_{Imperial College London, London, SW7 2AZ, United Kingdom}

33_{University of Iowa, Iowa City, Iowa 52242, USA} 34_{Iowa State University, Ames, Iowa 50011-3160, USA}

35_{Universit¨at Karlsruhe, Institut f¨ur Experimentelle Kernphysik, D-76021 Karlsruhe, Germany} 36_{Laboratoire de l’Acc´el´erateur Lin´eaire, F-91898 Orsay, France}

37_{Lawrence Livermore National Laboratory, Livermore, California 94550, USA} 38_{University of Liverpool, Liverpool L69 72E, United Kingdom} 39_{Queen Mary, University of London, E1 4NS, United Kingdom}

40_{University of London, Royal Holloway and Bedford New College, Egham, Surrey TW20 0EX, United Kingdom} 41_{University of Louisville, Louisville, Kentucky 40292, USA}

42_{University of Manchester, Manchester M13 9PL, United Kingdom} 43_{University of Maryland, College Park, Maryland 20742, USA} 44_{University of Massachusetts, Amherst, Massachusetts 01003, USA}

45_{Massachusetts Institute of Technology, Laboratory for Nuclear Science, Cambridge, Massachusetts 02139, USA} 46_{McGill University, Montr´eal, Qu´ebec, Canada H3A 2T8}

47_{Universit`a di Milano, Dipartimento di Fisica and INFN, I-20133 Milano, Italy} 48_{University of Mississippi, University, Mississippi 38677, USA}

49_{Universit´e de Montr´eal, Physique des Particules, Montr´eal, Qu´ebec, Canada H3C 3J7} 50_{Mount Holyoke College, South Hadley, Massachusetts 01075, USA}

51_{Universit`a di Napoli Federico II, Dipartimento di Scienze Fisiche and INFN, I-80126, Napoli, Italy}

52_{NIKHEF, National Institute for Nuclear Physics and High Energy Physics, NL-1009 DB Amsterdam, The Netherlands} 53_{University of Notre Dame, Notre Dame, Indiana 46556, USA}

54_{Ohio State University, Columbus, Ohio 43210, USA} 55_{University of Oregon, Eugene, Oregon 97403, USA}

56_{Universit`a di Padova, Dipartimento di Fisica and INFN, I-35131 Padova, Italy}

57_{Universit´es Paris VI et VII, Laboratoire de Physique Nucl´eaire et de Hautes Energies, F-75252 Paris, France} 58_{University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA}

59_{Universit`a di Perugia, Dipartimento di Fisica and INFN, I-06100 Perugia, Italy}

60_{Universit`a di Pisa, Dipartimento di Fisica, Scuola Normale Superiore and INFN, I-56127 Pisa, Italy} 61_{Prairie View A&M University, Prairie View, Texas 77446, USA}

62_{Princeton University, Princeton, New Jersey 08544, USA}

63_{Universit`a di Roma La Sapienza, Dipartimento di Fisica and INFN, I-00185 Roma, Italy} 64_{Universit¨at Rostock, D-18051 Rostock, Germany}

65_{Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 0QX, United Kingdom} 66_{DSM/Dapnia, CEA/Saclay, F-91191 Gif-sur-Yvette, France}

67_{University of South Carolina, Columbia, South Carolina 29208, USA} 68_{Stanford Linear Accelerator Center, Stanford, California 94309, USA}

69_{Stanford University, Stanford, California 94305-4060, USA} 70_{State University of New York, Albany, New York 12222, USA}

71_{University of Tennessee, Knoxville, Tennessee 37996, USA} 72_{University of Texas at Austin, Austin, Texas 78712, USA} 73_{University of Texas at Dallas, Richardson, Texas 75083, USA}

74_{Universit`a di Torino, Dipartimento di Fisica Sperimentale and INFN, I-10125 Torino, Italy</sub> 75<sub>Universit`a di Trieste, Dipartimento di Fisica and INFN, I-34127 Trieste, Italy}

76_{IFIC, Universitat de Valencia-CSIC, E-46071 Valencia, Spain} 77_{Vanderbilt University, Nashville, Tennessee 37235, USA}

78_{University of Victoria, Victoria, British Columbia, Canada V8W 3P6} 79_{Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom}

80_{University of Wisconsin, Madison, Wisconsin 53706, USA} 81_{Yale University, New Haven, Connecticut 06511, USA}

(Dated: September 29, 2018)

We report two novel determinations of |Vub| with reduced model dependence, based on mea-surements of the mass distribution of the hadronic system in semileptonic B decays. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson from Υ(4S) → BB events. In one approach, we combine the inclusive B → Xuℓ¯ν rate, integrated up to a maximum hadronic mass mX < 1.67 GeV/c2, with a measurement of the inclusive B → Xsγ photon energy spectrum. We obtain |Vub| = (4.43 ± 0.38stat± 0.25syst± 0.29theo) × 10−3. In another approach we measure the total B → Xuℓ¯ν rate over the full phase space and find |Vub| = (3.84 ± 0.70stat± 0.30syst± 0.10theo) × 10−3. PACS numbers: 13.20.He, 12.15.Hh, 14.40.Nd

The measurement of the element Vub of the

Cabibbo-Kobayashi-Maskawa quark-mixing matrix [1] plays a crit-ical role in testing the consistency of the Standard Model description of CP violation. The uncertainties in existing measurements [2, 3] are dominantly due to uncertainties in the b-quark mass mb and the modeling of the Fermi

motion of the b quark inside the B meson [4]. In this paper, we present two techniques to extract |Vub| from

inclusive B → Xuℓ¯ν [5] decays where these

uncertain-ties are significantly reduced. Neither method has been previously implemented experimentally.

Leibovich, Low, and Rothstein (LLR) have presented a prescription to extract |Vub| with reduced model

depen-dence from either the lepton energy or the hadronic mass mX [6]. A technique utilizing weight functions had been

proposed previously by Neubert [4]. The calculations of LLR are accurate up to corrections of order α2

s and

(ΛmB/(ζ mb))2, where ζ is the experimental maximum

hadronic mass up to which the B → Xuℓ¯ν decay rate is

determined and Λ ≈ ΛQCD. This method combines the

hadronic mass spectrum, integrated below ζ, with the high-energy end of the measured differential B → Xsγ

photon energy spectrum via the calculations of LLR. An alternative method [7] to reduce the model de-pendence is to measure the B → Xuℓ¯ν rate over the

entire mX spectrum. Since no extrapolation is

nec-essary to obtain the full rate, systematic uncertainties from mb and Fermi motion are much reduced.

Perturba-tive corrections are known to order α2

s. We extract the

B → Xuℓ¯ν rate from the hadronic mass spectrum up to

ζ = 2.5 GeV/c2 _{which corresponds to about 96% of the}

simulated hadronic mass spectrum.

The measurements presented here are based on a sample of 88.9 million BB pairs collected near the Υ(4S) resonance by the BA_BAR_{detector [8] at the}

PEP-II asymmetric-energy e+_e− _{storage rings operating at}

SLAC. The analysis uses Υ(4S) → BB events in which one of the B mesons decays hadronically and is fully re-constructed (Br) and the other decays semileptonically

(Bsl). To reconstruct a large sample of B mesons, we

fol-low the procedure described in Ref. [2] in which charged and neutral hadrons are combined with an exclusively reconstructed D meson to obtain combinations with an energy consistent with a B meson. While this approach results in a low overall event selection efficiency, it allows for the precise determination of the momentum, charge, and flavor of the Brcandidates.

We use Monte Carlo (MC) simulations of the BA_BAR

detector based on GEANT4 [9] to optimize selection crite-ria and to determine signal efficiencies and background distributions. Charmless semileptonic B → Xuℓ¯ν

de-cays are simulated as a combination of resonant three-body decays (Xu = π, ρ, ω, η, η′) [10], and decays to

non-resonant hadronic final states Xu [11] for which the

hadronization is performed by JETSET7.4 [12]. The ef-fect of Fermi motion is implemented in the simulation using an exponential function [11] with the parameters mb = 4.79 GeV/c2 and λ1 = −0.24 GeV2/c4 [13]. The

simulation of the B → Xcℓ¯ν background uses a Heavy

Quark Effective Theory parameterization of form factors for B→ D∗_{ℓν [14] and models for B → Dπℓν, D}∗_{πℓν [15]}

and B → Dℓν, D∗∗_{ℓν [10] decays.}

Semileptonic Bslcandidates are identified by the

pres-ence of at least one electron or muon with momentum p∗

ℓ > 1 GeV/c in the Bsl rest frame. For charged Br

candidates, we require the charge of the lepton to be consistent with a primary decay of a Bsl. For neutral

Br candidates, both charge-flavor combinations are

re-tained and the average B0_-B0 _{mixing rate [16] is used to}

determine the primary lepton yield. Electrons (muons) are identified [17] (Ref. [8]), with a 92% (60–75%) aver-age efficiency and a hadron misidentification rate ranging between 0.05% and 0.1% (1–3%).

The hadronic system X in the B→ Xℓ¯ν decays is re-constructed from charged tracks and energy depositions in the calorimeter that are not associated with the Br

candidate or the identified lepton. The neutrino four-momentum pν is estimated from the missing momentum

four-vector pmiss= pΥ(4S)− pBr− pX− pℓ, where all mo-menta are measured in the laboratory frame and pΥ(4S)

] 2 [GeV/c X m 0 1 2 3 4 5 Events / Bin 0 100 200 300 400 ] 2 [GeV/c X m 0 1 2 3 4 5 Events / Bin 0 100 200 300 400 Data ν u l → b ν c l → b Other a) ] 2 [GeV/c X m 0 1 2 3 4 5 Events / Bin -10 0 10 20 30 ] 2 [GeV/c X m 0 1 2 3 4 5 Events / Bin -10 0 10 20 30 Data ν u l → b b)

FIG. 1: The mX distributions (without combinatorial back-grounds) for B → Xℓ¯ν candidates: a) data (points) and fit components after the minimum-χ2 _{fit, and b) data and} sig-nal MC after subtraction of the B → Xcℓ¯ν and other back-grounds. The upper edge of the eighth bin is chosen to be at mX = 2.5 GeV/c2. This fit result, with χ2 = 10.2 for 11 degrees of freedom, is used to extract the number of signal events below 2.5 GeV/c2_.

refers to the Υ(4S) momentum.

To select B → Xuℓ¯ν candidates we require exactly one

lepton with p∗

ℓ > 1 GeV/c in the event, charge

conserva-tion (QX+Qℓ+QBr= 0), and a missing four-momentum consistent with a neutrino hypothesis, i.e., missing mass consistent with zero (−1.0 < m2

miss < 0.5 GeV 2_/c4_),

|pmiss| > 0.3 GeV/c, and | cos θmiss| < 0.95, where θmiss

is the polar angle of the missing momentum three-vector pmiss. These criteria suppress the majority of B→ Xcℓ¯ν

decays that contain additional neutrinos or an unde-tected K0

L meson. Additionally we reject events with charged or neutral kaons (reconstructed as K0

S → π

+_π−

decays) in the decay products of the Bsl. We

sup-press B → D∗_{ℓν backgrounds by partial reconstruction}

of charged and neutral D∗ _{mesons via identification of}

charged and neutral slow pions. The reconstruction of the mass of the hadronic system is improved by a kine-matic fit that imposes four-momentum conservation, the equality of the masses of the two B mesons, and p2

ν= 0.

The resulting mXresolution is ∼ 250 MeV/c2on average.

The extraction of |Vub|/|Vts| from the selected events

starts from the equation [6] |Vub| |Vts| = 6α(1 + H γ mix)(C (0) 7 )2 π[I0(ζ) + I+(ζ)] × δRu (ζ) 1₂ , (1)

where δRu(ζ) is the partial charmless semileptonic decay

rate extracted from the number of B→ Xuℓ¯ν events up

to a limit ζ in the mX spectrum. Hmixγ accounts for

interferences between electromagnetic penguin operator O7 with O2and O8[18], and C7(0) is the effective Wilson

coefficient. The terms I0(ζ) and I+(ζ) are determined by

multiplying the photon energy spectrum dΓγ_/dE

γin B →

Xsγ decays [13] with weight functions [6] and integrating.

The weights are zero below a minimum photon energy Emin

γ = mB/2 − ζ/4.

In terms of measurable quantities, δRu(ζ) is

δRu(ζ) = Nu(ζ)f (ζ)B(B → Xℓ¯ν) Nslεu(ζ) × εsl ℓ εu ℓ ×ε sl reco εu reco . (2)

Here, Nu(ζ) is the number of reconstructed B → Xuℓ¯ν

events with mX < ζ, f (ζ) accounts for migration in

and out of the region below ζ due to finite mX

reso-lution, B(B → Xℓ¯ν) is the total inclusive semileptonic branching fraction, and εu(ζ) is the efficiency for

select-ing B → Xuℓ¯ν decays once a B → Xℓ¯ν decay has been

identified with a hadronic mass below ζ. Nsl is the

num-ber of observed fully reconstructed B meson decays with a charged lepton with momentum above 1 GeV/c, εsl

ℓ/εuℓ

corrects for the difference in the efficiency of the lep-ton momentum selection for B→ Xℓ¯ν and B → Xuℓ¯ν

decays, and εsl

reco/εureco accounts for the difference in

the efficiency of reconstructing a Br in events with a

B → Xℓ¯ν and B → Xuℓ¯ν decay. By measuring the ratio

of B → Xuℓ¯ν events to all semileptonic B decays many

systematic uncertainties cancel out.

We derive Nu(ζ) from the mX distribution with a

binned χ2 _{fit to four components: data, B → X} uℓ¯ν

signal MC, B → Xcℓ¯ν background MC, and a small

MC background from other sources (misidentified lep-tons, B→ Xτ ¯ντ, and charm decays), fixed relative to

the B → Xcℓ¯ν component. Nu(ζ) is determined after

the subtraction of the fitted background contributions. For all four contributions, the combinatorial background is determined, separately in each bin of the mX

distri-bution, with unbinned maximum likelihood fits to dis-tributions of the beam energy-substituted mass mES =

ps/4 − p2

B of the Br candidate, where

√

s is the e+_e−

center-of-mass energy. The mESfit uses an empirical

de-scription of the combinatorial background shape [19] with a signal shape [20] peaking at the B meson mass. The combinatorial background varies from 5% (low mX bins)

to 25% (high mX bins). The fitted mX distributions are

shown in Fig. 1 before (a) and after (b) subtraction of backgrounds. The mX bins are 300 MeV/c2 wide except

that one bin is widened such that its upper edge is at ζ. We extract Nsl = (3.253 ± 0.024) × 104 from an

un-binned maximum likelihood fit to the mES distribution

of all events with p∗

ℓ > 1 GeV/c. The efficiency

correc-tions εsl

ℓ/εuℓ = 0.82 ± 0.02stat, as well as εu(ζ) and f (ζ)

(see Table I) are derived from simulations, where we also find εsl

reco/εureco in agreement with one, assigning a 3%

uncertainty.

We study three categories of systematic uncertainties in the determination of |Vub|: uncertainties in the signal

extraction, the simulation of physics processes, and the theoretical description. The quoted uncertainties have been determined for a value of ζ = 1.67 GeV/c2 _where

the total uncertainty on |Vub| is found to be minimal.

Experimental uncertainties in the signal extraction arise from imperfect description of data by the detector

TABLE I: Quantities in Eq. 2 that depend on ζ and their sta-tistical uncertainties. The LLR (full rate) technique is given in the first (second) column.

ζ 1.67 GeV/c2 _{2.50 GeV/c}2 f 1.010 ± 0.005 0.998 ± 0.002 Nu 120 ± 17 135 ± 45 εu 0.231 ± 0.005 0.231 ± 0.004 δRu× 103 1.43 ± 0.21 1.59 ± 0.53 ] 2 [GeV/c 1 2 3 3 10 × | ub |V 2 4 6 8

_LLR

_Full

Rate

ζ

FIG. 2: |Vub| as a function of ζ with the LLR method (left) and for the determination with the full rate measurement (right). The error bars indicate the statistical uncertainty. They are correlated between the points and get larger for larger ζ due to larger background from B → Xcℓ¯ν. The total shaded area illustrates the theoretical uncertainty; the inner light shaded (yellow) area indicates the perturbative share of the uncertainty. The arrow indicates ζ = 1.67 GeV/c2_.

simulation. We assign 0.5% (0.5%, 0.8%) for the particle identification of electrons (µ, K±_{), 0.7% for the}

recon-struction efficiency of charged particles, and 0.8% for the resolution and reconstruction efficiency of neutral parti-cles. An additional 0.9% uncertainty is due to imperfect simulation of K0

L interactions. By changing the func-tion describing the signal shape in mES to a Gaussian

function and switching from an unbinned to a binned fit method we derive an uncertainty of 2.2%. An uncer-tainty of 0.8% is determined by letting the contribution from other sources (see above) to the mX spectrum float

freely in the minimum-χ2 _{fit. The uncertainties on the}

inclusive B → Xsγ photon energy spectrum are

propa-gated including the full correlation matrix between the individual bins.

The second category of systematic uncertainties arises from imperfections in the composition and dynamics of decays in the simulation, both in signal and back-ground. The uncertainties in the branching fractions of B → D(∗,∗∗)_{l¯νX decays [16] contribute 0.7%. The}

un-certainties in the form factors in B → D∗_{l¯ν decays [14]}

introduce a 0.3% uncertainty. Branching fractions of D-meson decay channels [16] contribute 0.2%. The relative contribution of the non-resonant final states has been var-ied by 20% resulting in an uncertainty of 0.5%. The

TABLE II: Summary of results and uncertainties on |Vub| for both approaches. The LLR (full rate) technique is given in the first (second) column.

ζ [ GeV/c2_{] 1.67 2.5} |Vub| × 103 4.43 3.84 B → Xuℓ¯ν stat. 7.7% 18.2% experimental syst. 3.3% 3.6% background model 1.0% 3.8% signal model 3.9% 5.6% theoretical 6.2% 2.6% B → Xsγ (stat., syst.) 3.5%, 2.0% — |Vcb| (exp., theo.) 1.0%, 1.7% —

branching fractions of the resonant final states have been varied by ±30% (π, ρ), ±40% (ω), and ±100% (η and η′ _{simultaneously) resulting in an uncertainties of 1.0%.}

An uncertainty of 0.7% due to imperfect description of hadronization is determined from the change observed when we saturate the spectrum with the non-resonant component alone. We derive a 1.3% uncertainty due to the imperfect modeling of the KK content in the Xu

system by varying the fraction of decays to s¯s-pairs by 30% for the non-resonant contribution [21]. Even though the extraction of |Vub| does not explicitly depend on a

model for Fermi motion, there is still a residual depen-dency via the simulation of signal events. By varying the Fermi motion parameters mband λ1 within their

respec-tive uncertainties, taking correlations into account [13], we derive an uncertainty of 3.5%.

We calculate theoretical uncertainties in the weighting technique by varying the input parameters and repeating the weighting procedure including the calculation of all variables: H_mixγ , αS, and Wilson-coefficients. We vary

α between α(mb) and α(mW) with a central value of

1/130.3 and find an uncertainty of less than 1%. For perturbative effects, an uncertainty of 2.9% is derived by varying the renormalization scale µ between mb/2 and

2mb. Non-perturbative effects are expected to be of the

order (ΛmB/(ζ mb))2, where Λ = 500 MeV/c2 [22],

re-sulting in an uncertainty of 5.4%. Theoretical uncer-tainties in the measurement via the full rate are taken from Ref. [23] to be 1.2% (QCD) and 2.2% (HQE). Table II provides a summary of the uncertainties for ζ = 1.67 GeV/c2 _{and for ζ = 2.5 GeV/c}2_.

Finally, we present two different determinations of |Vub|. First, using the weighting technique with the

pho-ton energy spectrum in B → Xsγ decays from Ref. [13],

the hadronic mass spectrum up to a value of ζ = 1.67 GeV/c2_{, we find |V}

ub|/|Vts| = 0.107 ± 0.009stat ±

0.006syst± 0.007theo. If we assume the CKM matrix is

from Ref. [24], we derive

|Vub| = (4.43 ± 0.38 ± 0.25 ± 0.29) × 10−3,

where the first error is the statistical uncertainty from B → Xuℓ¯ν and from B → Xsγ added in quadrature,

the second (third) is systematic (theoretical). Second, we determine |Vub| from a measurement of the full mX

spectrum, i.e., up to a value of ζ = 2.5 GeV/c2_{, and find}

|Vub| = (3.84 ± 0.70stat± 0.30syst± 0.10theo) × 10−3, using

the average B lifetime of τB = (1.604 ± 0.012) ps [16, 25].

The weighting technique is expected to break down at low values of ζ, since only a small fraction of the phase space is used. Figure 2 illustrates the dependence of the result, and its statistical and theoretical uncertainties, on variations of ζ and also compares it with the value of |Vub| determined from the full rate. The weighting

technique appears to be stable down to ζ ∼ 1.4 GeV/c2_.

The current uncertainties on the B →Xsγ photon energy

spectrum limit the sensitivity with which the behavior at high ζ can be probed.

The above results are consistent with previous mea-surements [2, 3] but have substantially smaller uncertain-ties from mb and the modeling of Fermi motion. Both

techniques are based on theoretical calculations that are distinct from other calculations normally employed to ex-tract |Vub| and, thus, provide a complementary

determi-nation of |Vub|.

We wish to thank Adam Leibovich, Ian Low, and Ira Rothstein for their help and support. We are grate-ful for the excellent luminosity and machine conditions provided by our PEP-II colleagues, and for the sub-stantial dedicated effort from the computing organiza-tions that support BA_BAR_{. The collaborating institutions}

wish to thank SLAC for its support and kind hospital-ity. This work is supported by DOE and NSF (USA), NSERC (Canada), IHEP (China), CEA and CNRS-IN2P3 (France), BMBF and DFG (Germany), INFN (Italy), FOM (The Netherlands), NFR (Norway), MIST (Russia), and PPARC (United Kingdom). Individuals have received support from the A. P. Sloan Founda-tion, Research CorporaFounda-tion, and Alexander von Hum-boldt Foundation.

∗ _{Also with the Johns Hopkins University, Baltimore,} Maryland 21218 , USA

† _{Also at Laboratoire de Physique Corpusculaire,} Clermont-Ferrand, France

‡ _{Also with Universit`a di Perugia, Dipartimento di Fisica,} Perugia, Italy

§ _{Now at Institute for Particle Physics, ETH Z¨urich,} CH-8093 Z¨urich, Switzerland

¶ _{Also with Universit`a della Basilicata, Potenza, Italy} ∗∗ _Deceased

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