학술논문
First Evidence for cos2β>0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity
Document Type
article
Author
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; Epifanov, D
Source
Physical Review Letters. 121(26)
Subject
Language
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.