Study of the CP asymmetry of B-0 -> J/psi K-S(0) decays in ALEPH

Barate R; Decamp D; Ghez P; Goy C; Lees JP; Merle E; Minard MN; Pietrzyk B; Bravo S; Casado MP; Chmeissani M; Crespo JM; Fernandez E; Fernandez Bosman M; Garrido L; Grauges E; Martinez M; Merino G; Miquel R; Mir LM; Pacheco A; Ruiz H; Colaleo A; Creanza D; de Palma M; Iaselli G; Maggi G; Maggi M; Nuzzo S; Ranieri A; Raso G; Ruggieri F; Selvaggi G; Silvestris L; Tempesta P; Tricomi A; Zito G; Huang X; Lin J; Ouyang Q; Wang T; Xie Y; Xu R; Xue S; Zhang J; Zhang L; Zhao W; Abbaneo D; Boix G; Buchmuller O; Cattaneo M; Cerutti F; Dissertori G; Drevermann H; Forty RW; Frank M; Greening TC; Hansen JB; Harvey J; Janot P; Jost B; Lehraus I; Mato P; Minten A; Moutoussi A; Ranjard F; Rolandi L; Schlatter D; Schmitt M; Schneider O; Spagnolo P; Tejessy W; Teubert F; Tournefier E; Wright AE; Ajaltouni Z; Badaud F; Chazelle G; Deschamps O; Falvard A; Gay P; Guicheney C; Henrard P; Jousset J; Michel B; Monteil S; Montret JC; Pallin D; Perret P; Podlyski F; Hansen JD; Hansen JR; Hansen PH; Nilsson BS; Petersen BA; Waananen A; Daskalakis G; Kyriakis A; Markou C; Simopoulou E; Vayaki A; Blondel A; Bonneaud G; Brient JC; Rouge A; Rumpf M; Swynghedauw M; Verderi M; Videau H; Focardi E; Parrini G; Zachariadou K; Antonelli A; Antonelli M; Bencivenni G; Bologna G; Bossi F; Campana P; Capon G; Chiarella V; Laurelli P; Mannocchi G; Murtas F; Murtas GP; Passalacqua L; Pepe Altarelli M; Halley AW; Lynch JG; Negus P; O'Shea V; Raine C; Teixeira Dias P; Thompson AS; Cavanaugh R; Dhamotharan S; Geweniger C; Hanke P; Hansper G; Hepp V; Kluge EE; Putzer A; Sommer J; Tittel K; Werner S; Wunsch M; Beuselinck R; Binnie DM; Cameron W; Dornan PJ; Girone M; Marinelli N; Sedgbeer JK; Thompson JC; Thomson E; Ghete VM; Girtler P; Kneringer E; Kuhn D; Rudolph G; Bowdery CK; Buck PG; Finch AJ; Foster F; Hughes G; Jones RWL; Robertson NA; Giehl I; Jakobs K; Kleinknecht K; Quast G; Renk B; Rohne E; Sander HG; Wachsmuth H; Zeitnitz C; Bonissent A; Carr J; Coyle P; Leroy O; Payre P; Rousseau D; Talby M; Aleppo M; Ragusa F; Dietl H; Ganis G; Heister A; Huttmann K; Lutjens G; Mannert C; Manner W; Moser HG; Schael S; Settles R; Stenzel H; Wiedenmann W; Wolf G; Azzurri P; Boucrot J; Callot O; Chen S; Cordier A; Davier M; Duflot L; Grivaz JF; Heusse P; Jacholkowska A; Le Diberder F; Lefrancois J; Lutz AM; Schune MH; Veillet JJ; Videau I; Yuan C; Zerwas D; Bagliesi G; Boccali T; Calderini G; Ciulli V; Foa L; Giassi A; Ligabue F; MESSINEO, ALBERTO MARIA; Palla F; Sanguinetti G; Sciaba A; Sguazzoni G; Tenchini R; TONELLI, GUIDO EMILIO; Verdini PG; Blair GA; Cowan G; Green MG; Medcalf T; Strong JA; von Wimmersperg Toeller JH; Clifft RW; Edgecock TR; Norton PR; Tomalin IR; Bloch Devaux B; Colas P; Emery S; Kozanecki W; Lancon E; Lemaire MC; Locci E; Perez P; Rander J; Renardy JF; Roussarie A; Schuller JP; Schwindling J; Trabelsi A; Vallage B; Black SN; Dann JH; Johnson RP; Kim HY; Konstantinidis N; Litke AM; McNeil MA; Taylor G; Booth CN; Cartwright S; Combley F; Lehto M; Thompson LF; Affholderbach K; Bohrer A; Brandt S; Grupen C; Misiejuk A; Prange G; Sieler U; Giannini G; Gobbo B; Rothberg J; Wasserbaech S; Armstrong SR; Cranmer K; Elmer P; Ferguson DPS; Gao Y; Gonzalez S; Hayes OJ; Hu H; Jin S; Kile J; McNamara PA; Nielsen J; Orejudos W; Pan YB; Saadi Y; Scott IJ; Walsh J; Wu SL; Wu X; Zobernig G.

doi:10.1016/S0370-2693(00)01091-1

The decay B-0 --> J/psi K-S(0) is reconstructed with J/psi --> e(+)e(-) or mu (+)mu (-) and K-S(0) --> pi (+)pi (-). From the full ALEPH dataset at LEP1 of about 4 million hadronic Z decays, 23 candidates are selected with an estimated purity of 71%, They are used to measure the CP asymmetry of this decay, given by sin 2 beta in the Standard Model, with the result sin 2 beta = 0.84(-1.04)(+0.82) +/- 0.16. This is combined with existing measurements from other experiments, and increases the confidence level that CP violation has been observed in this channel to 98%. (C) 2000 Elsevier Science B.V. All rights reserved.