Measurements of J /psi and psi(2S)decays into Lambda anti-Lambdand Lambda anti-Lambda eta

作者：F. De Mori, J.Z. Bai, Y. Ban, X. Z. Cai, H. F. Chen, H. S. Chen, H. X. Chen, J. C. Chen, Jin Chen, Y. B. Chen, Y. P. Chu, Y. S. Dai, L.Y. Diao, Z. Y. Deng, Qingshun Dong, S. X. Du, J. Fang, S. S. Fang, C. D. Fu, C. S. Gao, Yu Gao, Siyi Gu, Y. T. Gu, Y. Guo, Zhijun Guo, F. A. Harris, K. L. He, Mingming He, Y. K. Heng, Jiaxin Hou, H. M. Hu, Jianping Hu, T. Hu, G. S. Huang, X. T. Huang, X. B. Ji, X. S. Jiang, X. Y. Jiang, J. B. Jiao, D. P. Jin, S. Jin, Y. F. Lai, Gang Li, H. B. Li, J. Li, R. Y. Li, S. M. Li, W. D. Li, W. G. Li, Xin Li, X. N. Li, X. Q. Li, Y. F. Liang, H. Liao, B. J. Liu, C. X. Liu, F. Liu, Fang Liu, H. H. Liu, H. M. Liu, J. Liu, J. B. Liu, J. P. Liu, J. Liu, Q. Liu, R. G. Liu, Z. A. Liu, Yuequn Lou, F. X. Lu, G. R. Lu, J. G. Lu, C. L. Luo, F. C., H. L., L. L., Q. M., Z. P. Mao, X. H. Mo, J. Nie, S. L. Olsen, R. G. Ping, N. D. Qi, H. Qin, J. F. Qiu, Zhen-Yu Ren, G. Rong, X. D. Ruan, L. Y. Shan, Lei Shang, Chun Shen, D. L. Shen, X. Y. Shen, H. Y. Sheng, H. S. Sun, S. S. Sun, Y. Z. Sun, Z. J. Sun, X. Tang, G. L. Tong, G. S. Varner, D. Y. Wang, L. Wang, L. L. Wang, L. S. Wang, M. Wang, P. Wang, Peng Wang, W. F. Wang, Yu Wang, Z. Wang, Z. Y. Wang, Zheng Wang, C. Wei, D. H. Wei, Y. Weng, Ning Wu, X. M. Xia, X. X. Xie, G. F. Xu, X. P. Xu, Y. C. Xu, M.L. Yan, H. X. Yang, Y. Yang, M. H. Ye, Y. X. Ye, G. Yu, C. Z. Yuan, Y. Yuan, S.L. Zang, Yun Zeng, B. X. Zhang, B. Y. Zhang, C. C. Zhang, D. H. Zhang, H. Q. Zhang, Haiqiang Zhang, J. W. Zhang, J. Y. Zhang, S. H. Zhang, X. Y. Zhang, Yiyun Zhang, Z. X. Zhang, Z. P. Zhang, Dongli Zhao, J. W. Zhao, M. G. Zhao, P. P. Zhao, Wenzhen Zhao, Z. G. Zhao, H. Q. Zheng, J. P. Zheng, Z. P. Zheng, L. Zhou, K. J. Zhu, Q. M. Zhu, Y. C. Zhu, Y. S. Zhu, Z. A. Zhu, B. A. Zhuang, X.A. Zhuang, B. S. Zou · 发表于：arXiv (Cornell University) · 年份：2007 · 被引用次数：1 · 研究领域：Particle physics theoretical and experimental studies、Quantum Chromodynamics and Particle Interactions、High-Energy Particle Collisions Research

Using 58 million $J/\psi$ and 14 million $\psi(2S)$ events collected by the BESII detector at the BEPC, branching fractions or upper limits for the decays $J/\psi$ and $\psi(2S) \to \Lambda \bar{\Lambda}\pi^0$ and $\Lambda \bar{\Lambda}\eta$ are measured. For the isospin violating decays, the upper limits are determined to be ${\cal B}(J/\psi \to \Lambda \bar{\Lambda}\pi^0)<6.4\times 10^{-5}$ and ${\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\pi^0)<4.9\times 10^{-5}$ at the 90% confidence level. The isospin conserving process $J/\psi \to \Lambda \bar{\Lambda}\eta$ is observed for the first time, and its branching fraction is measured to be ${\cal B}(J/\psi \to \Lambda \bar{\Lambda}\eta)=(2.62\pm 0.60\pm 0.44)\times 10^{-4}$, where the first error is statistical and the second one is systematic. No $\Lambda \bar{\Lambda}\eta$ signal is observed in $\psi(2S)$ decays, and ${\cal B}(\psi(2S) \to \Lambda \bar{\Lambda}\eta)<1.2\times 10^{-4}$ is set at the 90% confidence level. Branching fractions of $J/\psi$ decays into $\Sigma^+ \pi^- bar{\Lambda}$ and $\bar{\Sigma}^- \pi^+ \Lambda$ are also reported, and the sum of these branching fractions is determined to be ${\cal B}(J/\psi \to \Sigma^+\pi^- \bar{\Lambda} + c.c.)=(1.52\pm 0.08\pm 0.16)\times 10^{-3}$.