Ablikim M, Bai J Z, Bai Y, Ban Y, Cai X, Chen H F, Chen H S, Chen H X, Chen J C, Chen Jin, Chen X D, Chen Y B, Chu Y P, Dai Y S, Deng Z Y, Du S X, Fang J, Fu C D, Gao C S, Gao Y N, Gu S D, Gu Y T, Guo Y N, Guo Z J, Harris F A, He K L, He M, Heng Y K, Hou J, Hu H M, Hu T, Huang G S, Huang X T, Huang Y P, Ji X B, Jiang X S, Jiao J B, Jin D P, Jin S, Lai Y F, Li H B, Li J, Li R Y, Li W D, Li W G, Li X L, Li X N, Li X Q, Liang Y F, Liao H B, Liu B J, Liu C X, Liu Fang, Liu Feng, Liu H H, Liu H M, Liu J B, Liu J P, Liu H B, Liu J, Liu Q, Liu R G, Liu S, Liu Z A, Lu F, Lu G R, Lu J G, Luo C L, Ma F C, Ma H L, Ma L L, Ma Q M, Malik M Q A, Mao Z P, Mo X H, Nie J, Olsen S L, Ping R G, Qi N D, Qin H, Qiu J F, Rong G, Ruan X D, Shan L Y, Shang L, Shen C P, Shen D L, Shen X Y, Sheng H Y, Sun H S, Sun S S, Sun Y Z, Sun Z J, Tang X, Tian J P, Tong G L, Varner G S, Wan X, Wang L, Wang L L, Wang L S, Wang P, Wang P L, Wang W F, Wang Y F, Wang Z, Wang Z Y, Wei C L, Wei D H, Weng Y, Wu N, Xia X M, Xie X X, Xu G F, Xu X P, Xu Y, Yan M L, Yang H X, Yang M, Yang Y X, Ye M H, Ye Y X, Yu C X, Yu G W, Yuan C Z, Yuan Y, Zang S L, Zeng Y, Zhang B X, Zhang B Y, Zhang C C, Zhang D H, Zhang H Q, Zhang H Y, Zhang J W, Zhang J Y, Zhang X Y, Zhang Y Y, Zhang Z X, Zhang Z P, Zhao D X, Zhao J W, Zhao M G, Zhao P P, Zhao Z G, Zheng H Q, Zheng J P, Zheng Z P, Zhou B Zhong L, Zhu K J, Zhu Q M, Zhu X W, Zhu Y C, Zhu Y S, Zhu Z A, Zhu Z L, Zhuang B A, Zou B S
Institute of High Energy Physics, Beijing 100049, People's Republic of China.
Phys Rev Lett. 2008 Mar 14;100(10):102003. doi: 10.1103/PhysRevLett.100.102003. Epub 2008 Mar 12.
The decays of J/psi --> etaphif(0)(980)[eta --> gammagamma, phi --> K(+) K(-), f(0)(980) --> pi(+)pi(-)] are analyzed using a sample of 5.8 x 10(7) J/psi events collected with the BESII detector at the Beijing Electron-Positron Collider. A structure at around 2.18 GeV/c(2) with about 5 sigma significance is observed in the phif(0)(980) invariant mass spectrum. A fit with a Breit-Wigner function gives the peak mass and width of m = 2.186+/-0.010(stat)+/-0.006(syst) GeV/c(2) and Gamma = 0.065+/-0.023(stat)+/-0.017(syst) GeV/c(2), respectively, which are consistent with those of Y(2175), observed by the BABAR Collaboration in the initial-state radiation process e(+)e(-) --> gamma(ISR) phif(0)(980). The production branching ratio is determined to be Br(J/psi --> etaY(2175))Br(Y(2175)- -> phif(0)(980))Br(f(0)(980) --> pi(+)pi(-)) = [3.23+/-0.75(stat)+/-0.73(syst)] x 10(-4), assuming that the Y(2175) is a 1(--) state.
利用北京正负电子对撞机上的北京谱仪II（BESII）探测器收集的5.8×10⁷个J/ψ事例样本，对J/ψ→ηφf₀(980)[η→γγ，φ→K⁺K⁻，f₀(980)→π⁺π⁻]衰变进行了分析。在φf₀(980)不变质量谱中观察到一个约2.18 GeV/c²处、显著性约为5σ的结构。用布赖特 - 维格纳函数拟合得到的峰值质量和宽度分别为m = 2.186±0.010（统计）±0.006（系统）GeV/c²和Γ = 0.065±0.023（统计）±0.017（系统）GeV/c²，这与BABAR合作组在初态辐射过程e⁺e⁻→γ(ISR)φf₀(980)中观测到的Y(2175)的结果一致。假设Y(2175)是一个1⁻态，确定其产生分支比为Br(J/ψ→ηY(2175))Br(Y(2175)→φf₀(980))Br(f₀(980)→π⁺π⁻)=[3.23±0.75（统计）±0.73（系统）]×10⁻⁴ 。
