Measurement of branching fractions and search for $CP$ violation in $D^{0}\toπ^{+}π^{-}η$, $D^{0}\to K^{+}K^{-}η$, and $D^{0}\toϕη$ at Belle
Belle Collaboration, L. K. Li, A. J. Schwartz, K. Kinoshita, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Bab… 展开作者
Belle Collaboration, L. K. Li, A. J. Schwartz, K. Kinoshita, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, V. Aulchenko, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, J. Bennett, M. Bessner, T. Bilka, J. Biswal, A. Bobrov, G. Bonvicini, A. Bozek, M. Bra\v, P. Branchini, T. E. Browder, A. Budano, M. Campajola, D. \v, M. -C. Chang, P. Chang, V. Chekelian, A. Chen, Y. Q. Chen, B. G. Cheon, K. Chilikin, H. E. Cho, K. Cho, S. -J. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, S. Das, N. Dash, G. De Nardo, G. De Pietro, R. Dhamija, F. Di Capua, Z. Dole\v, T. V. Dong, S. Eidelman, D. Epifanov, T. Ferber, B. G. Fulsom, R. Garg, V. Gaur, A. Giri, P. Goldenzweig, B. Golob, E. Graziani, T. Gu, Y. Guan, C. Hadjivasiliou, S. Halder, K. Hayasaka, W. -S. Hou, K. Inami, A. Ishikawa, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, E. -J. Jang, S. Jia, Y. Jin, K. K. Joo, K. H. Kang, G. Karyan, C. Kiesling, C. H. Kim, D. Y. Kim, K. -H. Kim, S. H. Kim, Y. -K. Kim, P. Kody\v, T. Konno, A. Korobov, S. Korpar, E. Kovalenko, P. Kri\v, R. Kroeger, P. Krokovny, T. Kuhr, M. Kumar, K. Kumara, A. Kuzmin, Y. -J. Kwon, K. Lalwani, M. Laurenza, S. C. Lee, C. H. Li, L. Li Gioi, J. Libby, K. Lieret, D. Liventsev, M. Masuda, D. Matvienko, M. Merola, F. Metzner, K. Miyabayashi, R. Mizuk, G. B. Mohanty, T. Mori, M. Nakao, Z. Natkaniec, A. Natochii, L. Nayak, M. Nayak, M. Niiyama, N. K. Nisar, S. Nishida, K. Nishimura, H. Ono, P. Oskin, P. Pakhlov, G. Pakhlova, S. Pardi, S. -H. Park, A. Passeri, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, T. Podobnik, V. Popov, E. Prencipe, M. T. Prim, N. Rout, G. Russo, D. Sahoo, Y. Sakai, S. Sandilya, A. Sangal, L. Santelj, T. Sanuki, V. Savinov, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, M. Shapkin, C. Sharma, C. P. Shen, J. -G. Shiu, B. Shwartz, A. Sokolov, E. Solovieva, M. Stari\v, Z. S. Stottler, M. Sumihama, T. Sumiyoshi, M. Takizawa, K. Tanida, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, K. Uno, S. Uno, S. E. Vahsen, R. Van Tonder, G. Varner, A. Vinokurova, E. Waheed, C. H. Wang, M. -Z. Wang, P. Wang, X. L. Wang, S. Watanuki, E. Won, B. D. Yabsley, W. B. Yan, S. B. Yang, H. Ye, J. Yelton, J. H. Yin, Y. Yusa, Z. P. Zhang, V. Zhilich, V. Zhukova
We measure the branching fractions and $CP$ asymmetries for the singly Cabibbo-suppressed decays $D^{0}\toπ^{+}π^{-}η$, $D^{0}\to K^{+}K^{-}η$, and $D^{0}\toϕη$, using 980 fb$^{-1}$ of data from the Belle experiment at the KEKB $e^+e^-$ collider. We obtain \begin{eqnarray} \mathcal{B}(D^{0}\toπ^{+}π^{-}η) & = & [1.22\pm 0.02\,({\rm stat})\pm 0.02\,({\rm syst})\pm 0.03\,(\mathcal{B}_{\rm ref})]\times 10^{-3}\,, \nonumber \\ \mathcal{B}(D^{0}\to K^{+}K^{-}η) & = & [1.80\,^{+0.07}_{-0.06}\,({\rm stat})\pm 0.04\,({\rm syst})\pm 0.05\,(\mathcal{B}_{\rm ref})]\times 10^{-4}\,, \nonumber \\ \mathcal{B}(D^{0}\toϕη) & = & [1.84\pm 0.09\,({\rm stat})\pm 0.06\,({\rm syst})\pm 0.05\,(\mathcal{B}_{\rm ref})]\times 10^{-4}\,, \nonumber \end{eqnarray} where the third uncertainty ($\mathcal{B}_{\rm ref}$) is from the uncertainty in the branching fraction of the reference mode $D^{0}\to K^{-}π^{+}η$. The color-suppressed decay $D^{0}\toϕη$ is observed for the first time, with very high significance. The results for the $CP$ asymmetries are \begin{eqnarray} A_{CP}(D^{0}\toπ^{+}π^{-}η) & = & [0.9\pm 1.2\,({\rm stat})\pm 0.5\,({\rm syst})]\%\,, \nonumber \\ A_{CP}(D^{0}\to K^{+}K^{-}η) & = & [-1.4\pm 3.3\,({\rm stat})\pm 1.1\,({\rm syst})]\%\,, \nonumber \\ A_{CP}(D^{0}\toϕη)&= & [-1.9\pm 4.4\,({\rm stat})\pm 0.6\,({\rm syst})]\%\,. \nonumber \end{eqnarray} The results for $D^{0}\toπ^{+}π^{-}η$ are a significant improvement over previous results. The branching fraction and $A_{CP}$ results for $D^{0}\to K^{+}K^{-}η$, and the $A_{CP}$ result for $D^{0}\toϕη$, are the first such measurements. No evidence for $CP$ violation is found in any of these decays.
Belle II合作在SuperKEKB能量非对称e+ e对撞机上运行一个大幅升级的Belle探测器。Belle II将于2018年开始记录在Upperdance（4S）能量下的碰撞，目标是到2025年收集50 ab^{-1}的数据，是Belle实验的50倍。我们报告了测量与电荷宇称破坏相关的量的前景，特别强调了Cabibbo-Kobayashi-Maskawa角phi_3（γ）和与夸克混合矩阵元Vub相关的半轻子B介子衰变中的可观测量。
Measurements of $\boldsymbol{B\rightarrow Kπ}$ and $\boldsymbol{B\rightarrow ππ}$ Branching Fractions and $\boldsymbol{\mathcal{A}_{CP}}$ Asymmetries at Belle II
Belle II 测量了多种 $B\to K\pi$ 和 $B\to\pi\pi$ 衰变的分支比及直接 CP 不对称性，通过同位旋求和规则检验标准模型，并测量了 CKM 角 $\phi_2$ 相关的衰变，结果与标准模型预期一致。
我们报道了三体无粲衰变B+=>K+pi+pi-，B_0 => K_0 pi +pi-和B+=>K+K+K-的Dalitz分析结果，包括在B+=>K+pi+pi-模式中寻找直接的CP破坏.报道了一些准二体中间态的分支分数。我们还观察到在B+-=>rho（770）0 K +-通道中存在大的直接CP破坏的3.9 σ显著性证据。这是荷电介子衰变中CP破坏的第一个证据。使用Dalitz分析技术获得的结果与大数据样本的BBbar对收集的Belle探测器在KEKB非对称能量e+e-对撞机。
