1. First Evidence for cos2β>0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity
- Author
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Adachi, I, Adye, T, Ahmed, H, Ahn, JK, Aihara, H, Akar, S, Alam, MS, Albert, J, Anulli, F, Arnaud, N, Asner, DM, Aston, D, Atmacan, H, Aushev, T, Ayad, R, Babu, V, Badhrees, I, Bakich, AM, Banerjee, Sw, Bansal, V, Barlow, RJ, Batignani, G, Beaulieu, A, Behera, P, Bellis, M, Ben-Haim, E, Bernard, D, Bernlochner, FU, Bettarini, S, Bettoni, D, Bevan, AJ, Bhardwaj, V, Bhuyan, B, Bianchi, F, Biasini, M, Biswal, J, Blinov, VE, Bomben, M, Bondar, A, Bonneaud, GR, Bozek, A, Bozzi, C, Bračko, M, Browder, TE, Brown, DN, Bünger, C, Burchat, PR, Buzykaev, AR, Calabrese, R, Calcaterra, A, Calderini, G, Di Carlo, S, Carpinelli, M, Cartaro, C, Casarosa, G, Cenci, R, Chao, DS, Chauveau, J, Cheaib, R, Chen, A, Chen, C, Cheng, CH, Cheon, BG, Chilikin, K, Cho, K, Choi, Y, Choudhury, S, Chrzaszcz, M, Cibinetto, G, Cinabro, D, Cochran, J, Coleman, JP, Convery, MR, Cowan, G, Cowan, R, Cremaldi, L, Cunliffe, S, Dash, N, Davier, M, Davis, CL, De Mori, F, De Nardo, G, Denig, AG, de Sangro, R, Dey, B, Di Lodovico, F, Dittrich, S, Doležal, Z, Dorfan, J, Drásal, Z, Druzhinin, VP, Dunwoodie, W, Ebert, M, Echenard, B, Eidelman, S, Eigen, G, Eisner, AM, Emery, S, and Epifanov, D
- Subjects
Nuclear and Plasma Physics ,Particle and High Energy Physics ,Physical Sciences ,BABAR Collaboration ,Belle Collaboration ,hep-ex ,Mathematical Sciences ,Engineering ,General Physics ,Mathematical sciences ,Physical sciences - Abstract
We present first evidence that the cosine of the CP-violating weak phase 2β is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B^{0}→D^{(*)}h^{0} with D→K_{S}^{0}π^{+}π^{-} decays, where h^{0}∈{π^{0},η,ω} denotes a light unflavored and neutral hadron. The measurement is performed combining the final data sets of the BABAR and Belle experiments collected at the ϒ(4S) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain (471±3)×10^{6}BB[over ¯] pairs recorded by the BABAR detector and (772±11)×10^{6}BB[over ¯] pairs recorded by the Belle detector. The results of the measurement are sin2β=0.80±0.14(stat)±0.06(syst)±0.03(model) and cos2β=0.91±0.22(stat)±0.09(syst)±0.07(model). The result for the direct measurement of the angle β of the CKM Unitarity Triangle is β=[22.5±4.4(stat)±1.2(syst)±0.6(model)]°. The measurement assumes no direct CP violation in B^{0}→D^{(*)}h^{0} decays. The quoted model uncertainties are due to the composition of the D^{0}→K_{S}^{0}π^{+}π^{-} decay amplitude model, which is newly established by performing a Dalitz plot amplitude analysis using a high-statistics e^{+}e^{-}→cc[over ¯] data sample. CP violation is observed in B^{0}→D^{(*)}h^{0} decays at the level of 5.1 standard deviations. The significance for cos2β>0 is 3.7 standard deviations. The trigonometric multifold solution π/2-β=(68.1±0.7)° is excluded at the level of 7.3 standard deviations. The measurement resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle.
- Published
- 2018