Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons into definite flavor states (B0 or B̅ 0), and J/ψKL0 or cc̅ KS0 final states (referred to as B+ or B-), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, B̅ 0→B- and B-→B̅ 0, as a function of the time difference between the two B decays. Using 468×106 BB̅ pairs produced in Υ(4S) decays collected by the BABAR detector at SLAC, we measure T-violating parameters in the time evolution of neutral B mesons, yielding ΔST+=-1.37±0.14(stat)±0.06(syst) and ΔST-=1.17±0.18(stat)±0.11(syst). These nonzero results represent the first direct observation of T violation through the exchange of initial and final states in transitions that can only be connected by a T-symmetry transformation.
Observation of time-reversal violation in the B^{0} meson system / J. Lees, V. Poireau, V. Tisserand, J. Garra Tico, E. Grauges, A. Palano, G. Eigen, B. Stugu, D. Brown, L. Kerth, Y. Kolomensky, G. Lynch, H. Koch, T. Schroeder, D. Asgeirsson, C. Hearty, T. Mattison, J. McKenna, R. So, A. Khan, V. Blinov, A. Buzykaev, V. Druzhinin, V. Golubev, E. Kravchenko, A. Onuchin, S. Serednyakov, Y. Skovpen, E. Solodov, K. Todyshev, A. Yushkov, M. Bondioli, D. Kirkby, A. Lankford, M. Mandelkern, H. Atmacan, J. Gary, F. Liu, O. Long, G. Vitug, C. Campagnari, T. Hong, D. Kovalskyi, J. Richman, C. West, A. Eisner, J. Kroseberg, W. Lockman, A. Martinez, B. Schumm, A. Seiden, D. Chao, C. Cheng, B. Echenard, K. Flood, D. Hitlin, P. Ongmongkolkul, F. Porter, A. Rakitin, R. Andreassen, Z. Huard, B. Meadows, M. Sokoloff, L. Sun, P. Bloom, W. Ford, A. Gaz, U. Nauenberg, J. Smith, S. Wagner, R. Ayad, W. Toki, B. Spaan, K. Schubert, R. Schwierz, D. Bernard, M. Verderi, P. Clark, S. Playfer, D. Bettoni, C. Bozzi, R. Calabrese, G. Cibinetto, E. Fioravanti, I. Garzia, E. Luppi, M. Munerato, L. Piemontese, V. Santoro, R. Baldini-Ferroli, A. Calcaterra, R. de Sangro, G. Finocchiaro, P. Patteri, I. Peruzzi, M. Piccolo, M. Rama, A. Zallo, R. Contri, E. Guido, M. Lo Vetere, M. Monge, S. Passaggio, C. Patrignani, E. Robutti, B. Bhuyan, V. Prasad, C. Lee, M. Morii, A. Edwards, A. Adametz, U. Uwer, H. Lacker, T. Lueck, P. Dauncey, U. Mallik, C. Chen, J. Cochran, W. Meyer, S. Prell, A. Rubin, A. Gritsan, Z. Guo, N. Arnaud, M. Davier, D. Derkach, G. Grosdidier, F. Le Diberder, A. Lutz, B. Malaescu, P. Roudeau, M. Schune, A. Stocchi, G. Wormser, D. Lange, D. Wright, C. Chavez, J. Coleman, J. Fry, E. Gabathuler, D. Hutchcroft, D. Payne, C. Touramanis, A. Bevan, F. Di Lodovico, R. Sacco, M. Sigamani, G. Cowan, D. Brown, C. Davis, A. Denig, M. Fritsch, W. Gradl, K. Griessinger, A. Hafner, E. Prencipe, R. Barlow, G. Jackson, G. Lafferty, E. Behn, R. Cenci, B. Hamilton, A. Jawahery, D. Roberts, C. Dallapiccola, R. Cowan, D. Dujmic, G. Sciolla, R. Cheaib, D. Lindemann, P. Patel, S. Robertson, P. Biassoni, N. Neri, F. Palombo, S. Stracka, L. Cremaldi, R. Godang, R. Kroeger, P. Sonnek, D. Summers, X. Nguyen, M. Simard, P. Taras, G. De Nardo, D. Monorchio, G. Onorato, C. Sciacca, M. Martinelli, G. Raven, C. Jessop, J. LoSecco, W. Wang, K. Honscheid, R. Kass, J. Brau, R. Frey, N. Sinev, D. Strom, E. Torrence, E. Feltresi, N. Gagliardi, M. Margoni, M. Morandin, A. Pompili, M. Posocco, M. Rotondo, G. Simi, F. Simonetto, R. Stroili, S. Akar, E. Ben-Haim, M. Bomben, G. Bonneaud, H. Briand, G. Calderini, J. Chauveau, O. Hamon, P. Leruste, G. Marchiori, J. Ocariz, S. Sitt, M. Biasini, E. Manoni, S. Pacetti, A. Rossi, C. Angelini, G. Batignani, S. Bettarini, M. Carpinelli, G. Casarosa, A. Cervelli, F. Forti, M. Giorgi, A. Lusiani, B. Oberhof, E. Paoloni, A. Perez, G. Rizzo, J. Walsh, D. Lopes Pegna, J. Olsen, A. Smith, A. Telnov, F. Anulli, R. Faccini, F. Ferrarotto, F. Ferroni, M. Gaspero, L. Li Gioi, M. Mazzoni, G. Piredda, C. Bünger, O. Grünberg, T. Hartmann, T. Leddig, H. Schröder, C. Voss, R. Waldi, T. Adye, E. Olaiya, F. Wilson, S. Emery, G. Hamel de Monchenault, G. Vasseur, C. Yèche, D. Aston, D. Bard, R. Bartoldus, J. Benitez, C. Cartaro, M. Convery, J. Dorfan, G. Dubois-Felsmann, W. Dunwoodie, M. Ebert, R. Field, M. Franco Sevilla, B. Fulsom, A. Gabareen, M. Graham, P. Grenier, C. Hast, W. Innes, M. Kelsey, P. Kim, M. Kocian, D. Leith, P. Lewis, B. Lindquist, S. Luitz, V. Luth, H. Lynch, D. MacFarlane, D. Muller, H. Neal, S. Nelson, M. Perl, T. Pulliam, B. Ratcliff, A. Roodman, A. Salnikov, R. Schindler, A. Snyder, D. Su, M. Sullivan, J. Va’vra, A. Wagner, W. Wisniewski, M. Wittgen, D. Wright, H. Wulsin, C. Young, V. Ziegler, W. Park, M. Purohit, R. White, J. Wilson, A. Randle-Conde, S. Sekula, M. Bellis, P. Burchat, T. Miyashita, E. Puccio, M. Alam, J. Ernst, R. Gorodeisky, N. Guttman, D. Peimer, A. Soffer, P. Lund, S. Spanier, J. Ritchie, A. Ruland, R. Schwitters, B. Wray, J. Izen, X. Lou, F. Bianchi, D. Gamba, S. Zambito, L. Lanceri, L. Vitale, J. Bernabeu, F. Martinez-Vidal, A. Oyanguren, P. Villanueva-Perez, H. Ahmed, J. Albert, S. Banerjee, F. Bernlochner, H. Choi, G. King, R. Kowalewski, M. Lewczuk, I. Nugent, J. Roney, R. Sobie, N. Tasneem, T. Gershon, P. Harrison, T. Latham, H. Band, S. Dasu, Y. Pan, R. Prepost, S. Wu. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 109:21(2012), pp. 211801.211801.1-211801.211801.8.
Observation of time-reversal violation in the B^{0} meson system
P. Biassoni;N. Neri;F. Palombo;S. Stracka;
2012
Abstract
Although CP violation in the B meson system has been well established by the B factories, there has been no direct observation of time-reversal violation. The decays of entangled neutral B mesons into definite flavor states (B0 or B̅ 0), and J/ψKL0 or cc̅ KS0 final states (referred to as B+ or B-), allow comparisons between the probabilities of four pairs of T-conjugated transitions, for example, B̅ 0→B- and B-→B̅ 0, as a function of the time difference between the two B decays. Using 468×106 BB̅ pairs produced in Υ(4S) decays collected by the BABAR detector at SLAC, we measure T-violating parameters in the time evolution of neutral B mesons, yielding ΔST+=-1.37±0.14(stat)±0.06(syst) and ΔST-=1.17±0.18(stat)±0.11(syst). These nonzero results represent the first direct observation of T violation through the exchange of initial and final states in transitions that can only be connected by a T-symmetry transformation.
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