Evidence of a structure in $\bar{K}^{0} Λ_{c}^{+}$ consistent with a charged $Ξ_c(2930)^{+}$, and updated measurement of $\bar{B}^{0} \to \bar{K}^{0} Λ_{c}^{+} \barΛ_{c}^{-}$ at Belle
Belle Collaboration, Y. B. Li, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, I. Badhrees, S. Bahinipati, Y. Ban, V. Ba… 展开作者
Belle Collaboration, Y. B. Li, C. P. Shen, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, T. Aushev, R. Ayad, V. Babu, I. Badhrees, S. Bahinipati, Y. Ban, V. Bansal, P. Behera, C. Beleno, V. Bhardwaj, B. Bhuyan, J. Biswal, A. Bobrov, A. Bozek, M. Bracko, T. E. Browder, L. Cao, D. Cervenkov, P. Chang, V. Chekelian, A. Chen, B. G. Cheon, K. Chilikin, K. Cho, S. -K. Choi, Y. Choi, S. Choudhury, D. Cinabro, S. Cunliffe, N. Dash, S. Di Carlo, J. Dingfelder, Z. Dolezal, T. V. Dong, Z. Drasal, S. Eidelman, D. Epifanov, J. E. Fast, B. G. Fulsom, R. Garg, V. Gaur, N. Gabyshev, A. Garmash, M. Gelb, A. Giri, P. Goldenzweig, B. Golob, J. Haba, K. Hayasaka, S. Hirose, W. -S. Hou, T. Iijima, K. Inami, G. Inguglia, A. Ishikawa, R. Itoh, M. Iwasaki, Y. Iwasaki, W. W. Jacobs, I. Jaegle, H. B. Jeon, S. Jia, Y. Jin, K. K. Joo, A. B. Kaliyar, K. H. Kang, Y. Kato, T. Kawasaki, D. Y. Kim, J. B. Kim, S. H. Kim, K. Kinoshita, P. Kodyš, S. Korpar, D. Kotchetkov, P. Križan, R. Kroeger, P. Krokovny, T. Kuhr, Y. -J. Kwon, J. S. Lange, I. S. Lee, S. C. Lee, L. K. Li, L. Li Gioi, J. Libby, D. Liventsev, T. Luo, D. Matvienko, M. Merola, H. Miyata, R. Mizuk, H. K. Moon, T. Mori, R. Mussa, E. Nakano, T. Nanut, K. J. Nath, Z. Natkaniec, M. Nayak, N. K. Nisar, S. Nishida, K. Nishimura, K. Ogawa, S. Okuno, H. Ono, P. Pakhlov, G. Pakhlova, B. Pal, S. Pardi, H. Park, S. Paul, T. K. Pedlar, R. Pestotnik, L. E. Piilonen, V. Popov, E. Prencipe, A. Rostomyan, G. Russo, Y. Sakai, M. Salehi, S. Sandilya, L. Santelj, T. Sanuki, V. Savinov, O. Schneider, G. Schnell, C. Schwanda, Y. Seino, K. Senyo, O. Seon, M. E. Sevior, T. -A. Shibata, J. -G. Shiu, E. Solovieva, M. Starič, J. F. Strube, M. Sumihama, T. Sumiyoshi, M. Takizawa, U. Tamponi, K. Tanida, F. Tenchini, M. Uchida, T. Uglov, Y. Unno, S. Uno, Y. Usov, C. Van Hulse, R. Van Tonder, G. Varner, K. E. Varvell, V. Vorobyev, E. Waheed, B. Wang, C. H. Wang, M. -Z. Wang, P. Wang, X. L. Wang, S. Watanuki, E. Widmann, E. Won, H. Ye, J. Yelton, J. H. Yin, C. Z. Yuan, Y. Yusa, Z. P. Zhang, V. Zhilich, V. Zhukova, V. Zhulanov
We report evidence for the charged charmed-strange baryon $Ξ_{c}(2930)^+$ with a signal significance of 3.9$σ$ with systematic errors included. The charged $Ξ_{c}(2930)^+$ is found in its decay to $K_{S}^{0} Λ_{c}^+$ in the substructure of $\bar{B}^{0} \to K^{0}_{S} Λ_{c}^{+} \barΛ_{c}^{-}$ decays. The measured mass and width are $[2942.3 \pm 4.4 (\rm stat.) \pm 1.5(\rm syst.)]$~MeV/$c^{2}$ and $[14.8 \pm 8.8(\rm stat.) \pm 2.5(\rm syst.)]$~MeV, respectively, and the product branching fraction is $\cal{B}(\bar{B}^{0} \to Ξ_c(2930)^{+} \barΛ_{c}^{-}) \cal{B}(Ξ_c(2930)^{+}\to \bar{K}^{0} Λ_{c}^{+})=[2.37 \pm 0.51 (\rm stat.)\pm 0.31(\rm syst.)]\times 10^{-4}$. We also measure $\cal{B}(\bar{B}^{0} \to \bar{K}^{0} Λ_{c}^{+} \barΛ_{c}^{-}) = [3.99 \pm 0.76(\rm stat.) \pm 0.51(\rm syst.)] \times 10^{-4}$ with greater precision than previous experiments, and present the results of a search for the charmonium-like state $Y(4660)$ and its spin partner, $Y_η$, in the $Λ_{c}^{+}\barΛ_{c}^{-}$ invariant mass spectrum. No clear signals of the $Y(4660)$ or $Y_η$ are observed and the 90\% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of $(772\pm11)\times 10^{6} B\bar{B}$ pairs collected at the $Υ(4S)$ resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
Search for $B^0 \to p \bar{p}$, $Λ\barΛ$ and $B^+ \to p \barΛ$ at Belle
本文报道了基于140 fb^{-1}数据样本分析的无粲二体重子衰变B^0 \to p \bar{p}，B^0 \to \bar和B^+ \to p \bar的搜寻结果。我们对它们的分支分数设置了90%置信水平上限：B（B^0 \to p \bar{p}）< 4.1 x 10^{-7}，B（B^0 \to <$\bar <$）< 6.9 x 10^{-7}$，B（B^+ \to p \bar <$）< 4.9 x 10^{-7}。
Factorization and angular distribution asymmetries in charmful baryonic B decays
我们检验了广义因式分解方法的有效性，并计算了$\bar B^0\to Λ\bar p D^{(*)+}$中有趣的三体重子衰变的角关联。利用从重子$B$衰变中提取的类时重子形状因子，我们得到了与BELLE合作组最近的数据相一致的${\cal B}(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(1.85\pm 0.30,2.75\pm 0.24)\times 10^{-5}$，这表明基于因子分解的理论方法仍然有效.对于角分布的不对称性，我们发现${\cal A}_θ(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(-0.030\pm 0.002\,,+0.150\pm 0.000)$，这是与目前的测量一致。此外，我们预测，${\cal A}_θ(\bar B^0\to p\bar p D^{0},p\bar p D^{*0})=+0.04\pm 0.01$ .未来在BELLE和LHCb以及super-BELLE上对这些角关联的精确探索对于证明目前在迷人的三体重子衰变中的因式分解方法是重要的。
Belle II是Belle实验的重大升级，将在日本的$B$工厂SuperKEKB运行。在这里，我们讨论的预期灵敏度的美女II $D^0 - \bar{D}^0$混合和$CP$违反测量的魅力部门，这将受益于一个因素50增加统计和改进的顶点检测和粒子识别。本文讨论了纯轻子$D$介子衰变测量对确定CKM参数的影响。最后提出了一种新的风味标记方法，大大增加了$D^0$和$\bar{D}^0$的样本量。
Exclusion of multifold solutions of the CKM Unitarity Triangle by a time-dependent Dalitz plot analysis of $\bar B^0 \to D^{(*)0} h^0$ with $D^0 \to K^0_S π^+ π^-$ decays combining BABAR and Belle data
B lifetime and $B^0-\bar B^0$ mixing results from early Belle II data
在SuperKEKB能量不对称$e^+ e^-$对撞机上进行的Belle II实验是对日本KEK实验室B工厂设施的重大升级。机器的设计光度为$8\times 10^{35}$ cm $^{-2}$ s $^{-1}$，Belle II实验的目标是记录50 ab $^{-1}$的数据，比其前身多50倍。从2018年2月到7月，机器已经完成了调试运行，达到了$5.5\times 10^{33}$ cm $^{-2}$ s $^{-1}$的峰值光度，Belle II已经记录了大约0.5 fb $^{-1}$的数据样本。SuperKEKB已于二零一九年三月开始正式营运。我们使用该数据集来表征检测器在跟踪带电粒子、重建已知共振以及识别位移衰变顶点的能力方面的性能。为了评估实验的B物理能力，第一批基准之一包括测量B介子的寿命和$B^0-\bar B^0$混合频率。我们提出的第一个结果，基于样品的B介子衰变到强子和半轻子的最终状态。
