Measurement of branching fractions ofBdecays toK1(1270)πandK1(1400)πand determination of the CKM angleαfromB0→a1(1260)±π∓

Author(s): Aubert, B; Karyotakis, Y; Lees, JP; Poireau, V; Prencipe, E; Prudent, X; Tisserand, V; Garra Tico, J; Grauges, E; Martinelli, M; Palano, A; Pappagallo, M; Eigen, G; Stugu, B; Sun, L; Battaglia, M; Brown, DN; Hooberman, B; Kerth, LT; Kolomensky, YG; Lynch, G; Osipenkov, IL; Tackmann, K; Tanabe, T; Hawkes, CM; Soni, N; Watson, AT; Koch, H; Schroeder, T; Asgeirsson, DJ; Hearty, C; Mattison, TS; McKenna, JA; Barrett, M; Khan, A; Randle-Conde, A; Blinov, VE; Bukin, AD; Buzykaev, AR; Druzhinin, VP; Golubev, VB; Onuchin, AP; Serednyakov, SI; Skovpen, YI; Solodov, EP; Todyshev, KY; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, AJ; Lund, P; Mandelkern, M; Martin, EC; Stoker, DP; Atmacan, H; Gary, JW; Liu, F; Long, O; Vitug, GM; Yasin, Z; Sharma, V; Campagnari, C; Hong, TM; Kovalskyi, D; Mazur, MA; Richman, JD; Beck, TW; Eisner, AM; Heusch, CA; Kroseberg, J; Lockman, WS; Martinez, AJ; Schalk, T; Schumm, BA; Seiden, A; Wang, L; Winstrom, LO; Cheng, CH; Doll, DA; Echenard, B; Fang, F; Hitlin, DG; Narsky, I; Ongmongkolkul, P | Abstract: We report measurements of the branching fractions of neutral and charged B meson decays to final states containing a K1(1270) or K1(1400) meson and a charged pion. The data, collected with the BABAR detector at the SLAC National Accelerator Laboratory, correspond to 454×106 BB pairs produced in e+e-annihilation. We measure the branching fractions B(B0→K1(1270)+π-+K1(1400)+π-)=3.1-0.7+0.8×10-5 and B(B+→ K1(1270) 0π++K1(1400) 0π+)=2.9-1.7+2.9×10-5 (l8.2×10-5 at 90% confidence level), where the errors are statistical and systematic combined. The B0 decay mode is observed with a significance of 7.5σ, while a significance of 3.2σ is obtained for the B+decay mode. Based on these results, we estimate the weak phase α=(79±7±11)°from the time-dependent CP asymmetries in B0→a1(1260)±π decays. © 2010 The American Physical Society.