对λ不变质量谱中阈值增强的观测。

Observation of a threshold enhancement in the plambda invariant-mass spectrum.

作者信息

Ablikim M, Bai J Z, Ban Y, Bian J G, Cai X, Chang J F, Chen H F, Chen H S, Chen H X, Chen J C, Chen Jin, Chen Jun, Chen M L, Chen Y B, Chi S P, Chu Y P, Cui X Z, Dai H L, Dai Y S, Deng Z Y, Dong L Y, Du S X, Du Z Z, Fang J, Fang S S, Fu C D, Fu H Y, Gao C S, Gao Y N, Gong M Y, Gong W X, Gu S D, Guo Y N, Guo Y Q, Guo Z J, Harris F A, He K L, He M, He X, Heng Y K, Hu H M, Hu T, Huang G S, Huang L, Huang X P, Ji X B, Jia Q Y, Jiang C H, Jiang X S, Jin D P, Jin S, Jin Y, Lai Y F, Li F, Li G, Li H H, Li J, Li J C, Li Q J, Li R B, Li R Y, Li S M, Li W G, Li X L, Li X Q, Li X S, Liang Y F, Liao H B, Liu C X, Liu F, Liu Fang, Liu H M, Liu J B, Liu J P, Liu R G, Liu Z A, Liu Z X, Lu F, Lu G R, Lu J G, Luo C L, Luo X L, Ma F C, Ma J M, Ma L L, Ma Q M, Ma X Y, Mao Z P, Mo X H, Nie J, Nie Z D, Olsen S L, Peng H P, Qi N D, Qian C D, Qin H, Qiu J F, Ren Z Y, Rong G, Shan L Y, Shang L, Shen D L, Shen X Y, Sheng H Y, Shi F, Shi X, Sun H S, Sun S S, Sun Y Z, Sun Z J, Tang X, Tao N, Tian Y R, Tong G L, Varner G S, Wang D Y, Wang J X, Wang J Z, Wang K, Wang L, Wang L S, Wang M, Wang P, Wang P L, Wang S Z, Wang W F, Wang Y F, Wang Zhe, Wang Z, Wang Zheng, Wang Z Y, Wei C L, Wei D H, Wu N, Wu Y M, Xia X M, Xie X X, Xin B, Xu G F, Xu H, Xu Y, Xue S T, Yan M L, Yang F, Yang H X, Yang J, Yang S D, Yang Y X, Ye M, Ye M H, Ye Y X, Yi L H, Yi Z Y, Yu C S, Yu G W, Yuan C Z, Yuan J M, Yuan Y, Yue Q, Zang S L, Zeng Yu, Zeng Y, Zhang B X, Zhang B Y, Zhang C C, Zhang D H, Zhang H Y, Zhang J, Zhang J Y, Zhang J W, Zhang L S, Zhang Q J, Zhang S Q, Zhang X M, Zhang X Y, Zhang Y J, Zhang Y Y, Zhang Yiyun, Zhang Z P, Zhang Z Q, Zhao D X, Zhao J B, Zhao J W, Zhao M G, Zhao P P, Zhao W R, Zhao X J, Zhao Y B, Zhao Z G, Zheng H Q, Zheng J P, Zheng L S, Zheng Z P, Zhong X C, Zhou B Q, Zhou G M, Zhou L, Zhou N F, Zhu K J, Zhu Q M, Zhu Y C, Zhu Y S, Zhu Yingchun, Zhu Z A, Zhuang B A, Zou B S

机构信息

Institute of High Energy Physics, Beijing 100039, People's Republic of China.

出版信息

Phys Rev Lett. 2004 Sep 10;93(11):112002. doi: 10.1103/PhysRevLett.93.112002.

DOI:10.1103/PhysRevLett.93.112002

PMID:15447331

Abstract

An enhancement near the m(p)+M(Lambda) mass threshold is observed in the combined pLambda and pLambda invariant-mass spectrum from J/psi-->pK(-)Lambda;+c.c. decays. It can be fit with an S-wave Breit-Wigner resonance with a mass m=2075+/-12(stat)+/-5(syst) MeV and a width of Gamma=90+/-35(stat)+/-9(syst) MeV; it can also be fit with a P-wave Breit-Wigner resonance. Evidence for a similar enhancement is also observed in psi(')-->pK(-)Lambda;+c.c. decays. The analysis is based on samples of 5.8x10(7)J/psi and 1.4x10(7)psi(') decays accumulated in the BES II detector at the Beijing Electron-Positron Collider.

摘要

在J/ψ→pK⁻Λ⁺ + c.c.衰变产生的组合pΛ和pΛ不变质量谱中，观察到在m(p)+M(Λ)质量阈值附近有增强。它可以用一个质量m = 2075±12(统计)±5(系统)MeV、宽度Γ = 90±35(统计)±9(系统)MeV的S波布赖特-维格纳共振来拟合；也可以用一个P波布赖特-维格纳共振来拟合。在ψ(')→pK⁻Λ⁺ + c.c.衰变中也观察到了类似增强的证据。该分析基于在北京正负电子对撞机的BES II探测器中积累的5.8×10⁷次J/ψ衰变和1.4×10⁷次ψ(')衰变的样本。