Ablikim M. (布里克木麦迪娜阿)1, Bai J. Z. (景芝白)1, Bai Y. (羽白)1, Ban Y. (勇班)11, Cai X. (啸蔡)1, Chen H. F. (宏芳陈)17, Chen H. S. (和生陈)1, Chen J. C. (江川陈)1, Chen J. (进陈)1, Chen Y. B. (元柏陈)1, Chu Y. P. (元萍初)1, Dai Y. S. (又善戴)19, Deng Z. Y. (子艳邓)1, Du S. X. (书先杜)1,20, Fang J. (建方)1, Fu C. D. (成栋傅)1, Gao Y. (原宁高)15, Gu Y. T. (运厅顾)4, Guo Z. J. (子敬郭)16,21, Harris F. A.16, He K. L. (康林何)1, He M. (瑁何)13, Heng Y. K. (月昆衡)1, Hu H. M. (海明胡)1, Hussain T.1,22, Hu T. (涛胡)1, Huang G. S. (光顺黄)17, Huang X. T. (性涛黄)13, Huang Y. P. (燕萍黄)1, Hussain T.1,22, Ji X. B. (晓斌季)1, Jiang X. S. (晓山江)1, Jiao J. B. (健斌焦)13, Jin D. P. (大鹏金)1, Jin S. (山金)1, Li G. (刚李)1, Li H. B. (海波李)1, Li J. (金李)1, Li L. (蕾李)1, Li R. Y. (仁英李)1, Li W. D. (卫东李)1, Li W. G. (卫国李)1, Li X. L. (晓玲李)13, Li X. N. (小男李)1, Li X. Q. (学潜李)10, Liang Y. F. (勇飞梁)14, Liu B. J. (北江刘)1, Liu C. X. (春秀刘)1, Liu Fang (芳刘)1, Liu Feng (峰刘)6, Liu H. B. (宏邦刘)4, Liu H. M. (怀民刘)1, Liu J. P. (觉平刘)18, Liu Q. (倩刘)16,23, Liu R. G. (荣光刘)1, Liu Z. A. (振安刘)1, Lu F. (峰吕)1, Lu G. R. (公儒鲁)5, Lu J. G. (军光吕)1, Luo X. L. (成林罗)9, Ma F. C. (凤才马)8, Ma H. L. (海龙马)1, Ma Q. M. (秋梅马)1, Malik M. Q. A.1,22, Mao Z. P. (泽普毛)1, Mo X. H. (晓虎莫)1, Nie J. (晶聂)1, Olsen S. L.12, Ping R. G. (荣刚平)1, Qiu J. F. (进发邱)1, Rong G. (刚荣)1, Ruan X. D. (向东阮)4, Shan L. Y. (连友单)1, Shang L. (雷尚)1, Shen C. P. (成平沈)16,24, Shen X. Y. (肖雁沈)1, Sheng H. Y. (华义盛)1, Sun S. S. (海生孙)1, Sun S. S. (胜森孙)1, Sun Y. Z. (永昭孙)1, Sun Z. J. (志嘉孙)1, Tang X. (晓唐)1, Tian J. P. (俊平田)15, Varner G. S.16, Wan X. (霞万)1, Wang L. (靓王)1, Wang L. L. (亮亮王)1, Wang L. S. (灵淑王)1, Wang P. (平王)1, Wang P. L. (佩良王)1, Wang Y. F. (贻芳王)1, Wang Z. (铮王)1, Wang Z. Y. (至勇王)1, Wei C. L. (诚林魏)1, Wei D. H. (代会魏)3, Wu N. (宁吴)1, Xu G. F. (国发许)1, Xu X. P. (新平徐)6,25, Xu Y. (晔徐)10, Yan M. L. (沐霖阎)17, Yang H. X. (洪勋杨)1, Yang M. (明杨)1, Yang Y. X. (永栩杨)3, Ye M. H. (铭汉叶)2, Ye Y. X. (云秀叶)17, Yu C. X. (纯旭喻)10, Yuan C. Z. (长征苑)1, Yuan Y. (野袁)1, Zeng Y. (云曾)7, Zhang B. X. (丙新张)1, Zhang B. Y. (炳云张)1, Zhang C. C. (长春张)1, Zhang D. H. (达华张)1, Zhang H. Q. (华桥张)1, Zhang H. Y. (红宇章)1, Zhang J. W. (家文张)1, Zhang J. Y. (建勇张)1, Zhang X. Y. (学尧张)13, Zhang Y. Y. (一云张)14, Zhang Z. P. (子平张)17, Zhao J. W. (京伟赵)1, Zhao M. G. (明刚赵)10, Zhao P. P. (平平赵)1, Zhao Z. G. (政国赵)17, Zheng B. (波郑)1, Zheng H. Q. (海青郑)11, Zheng J. P. (建平郑)1, Zheng Z. P. (志鹏郑)1, Zhong B. (彬钟)1, Zhou L. (莉周)1, Zhu K. J. (科军朱)1, Zhu Q. M. (启明朱)1, Zhu X. W. (兴旺朱)1, Zhu Y. S. (永生朱)1, Zhu Z. A. (自安朱)1 and Zou B. S. (冰松邹)1
2012 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd
Chinese Physics C,
Volume 36,
Number 11
Citation Ablikim M. et al 2012 Chinese Phys. C36 1031DOI 10.1088/1674-1137/36/11/001
Based on 58 million J/ψ events collected by the BES II detector at the BEPC, J/ψ → Λ π+π− is observed for the first time. The branching fraction is measured to be Br(J/ψ → Λ π+π−) = (4.30±0.13±0.99)×10−3, excluding the decays to intermediate states, namely J/ψ → Ξ−+, J/ψ → Σ(1385)−(1385)+, and J/ψ → Σ(1385)+(1385)−. The branching fractions for these intermediate resonance channels are measured to be: Br(J/ψ → Ξ−+) = (0.90±0.03±0.18)×10−3, Br(J/ψ → Σ(1385)−(1385)+) = (1.23±0.07±0.30)×10−3, and Br(J/ψ → Σ(1385)+(1385)−) = (1.50±0.08±0.38)×10−3, respectively. The angular distribution is of the form ∝ (1 + αcos2θ) with α = (0.35±0.29±0.06) for J/ψ → Ξ−+, α = (−0.54±0.22±0.10) for J/ψ → Σ(1385)−(1385)+, and α = (−0.35±0.25±0.06) for J/ψ → Σ(1385)+(1385)−.
π+π−
π+π− is observed for the first time. The branching fraction is measured to be Br(J/ψ → Λ
+, J/ψ → Σ(1385)−
(1385)+, and J/ψ → Σ(1385)+
∝ (1 + αcos2θ) with α = (0.35±0.29±0.06) for J/ψ → Ξ−