Measurements of J/ψ→pp̄

• DOI: 10.1016/j.physletb.2004.04.022
• Publication Date: 2004-05-14T10:36:43Z
• Authors: J.Z. Bai; Y. Ban; J.G. Bian; X. Cai; J.F. Chang; H.F. Chen; H.S. Chen; H.X. Chen; J. Chen; J.C. Chen; Jun Chen; M.L. Chen; Y.B. Chen; S.P. Chi; Y.P. Chu; X.Z. Cui; H.L. Dai; Y.S. Dai; Z.Y. Deng; L.Y. Dong; S.X. Du; Z.Z. Du; J. Fang; S.S. Fang; C.D. Fu; H.Y. Fu; L.P. Fu; C.S. Gao; M.L. Gao; Y.N. Gao; M.Y. Gong; W.X. Gong; S.D. Gu; Y.N. Guo; Y.Q. Guo; Z.J. Guo; S.W. Han; F.A. Harris; J. He; K.L. He; M. He; X. He; Y.K. Heng; H.M. Hu; T. Hu; G.S. Huang; L. Huang; X.P. Huang; X.B. Ji; Q.Y. Jia; C.H. Jiang; X.S. Jiang; D.P. Jin; S. Jin; Y. Jin; Y.F. Lai; 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. Li; W.G. Li; X.L. Li; X.Q. Li; X.S. Li; Y.F. Liang; H.B. Liao; C.X. Liu; Fang Liu; F. Liu; H.M. Liu; J.B. Liu; J.P. Liu; R.G. Liu; Y. Liu; Z.A. Liu; Z.X. Liu; G.R. Lu; F. Lu; J.G. Lu; C.L. Luo; X.L. Luo; F.C. Ma; J.M. Ma; L.L. Ma; X.Y. Ma; Z.P. Mao; X.C. Meng; X.H. Mo; J. Nie; Z.D. Nie; S.L. Olsen; H.P. Peng; N.D. Qi; C.D. Qian; H. Qin; J.F. Qiu; Z.Y. Ren; G. Rong; L.Y. Shan; L. Shang; D.L. Shen; X.Y. Shen; H.Y. Sheng; F. Shi; X. Shi; L.W. Song; H.S. Sun; S.S. Sun; Y.Z. Sun; Z.J. Sun; X. Tang; N. Tao; Y.R. Tian; G.L. Tong; G.S. Varner; D.Y. Wang; J.Z. Wang; L. Wang; L.S. Wang; M. Wang; Meng Wang; P. Wang; P.L. Wang; S.Z. Wang; W.F. Wang; Y.F. Wang; Zhe Wang; Z. Wang; Zheng Wang; Z.Y. Wang; C.L. Wei; N. Wu; Y.M. Wu; X.M. Xia; X.X. Xie; B. Xin; G.F. Xu; H. Xu; Y. Xu; S.T. Xue; M.L. Yan; W.B. Yan; F. Yang; H.X. Yang; J. Yang; S.D. Yang; Y.X. Yang; L.H. Yi; Z.Y. Yi; M. Ye; M.H. Ye; Y.X. Ye; C.S. Yu; G.W. Yu; C.Z. Yuan; J.M. Yuan; Y. Yuan; Q. Yue; S.L. Zang; Y. Zeng; B.X. Zhang; B.Y. Zhang; C.C. Zhang; D.H. Zhang; H.Y. Zhang; J. Zhang; J.M. Zhang; J.Y. Zhang; J.W. Zhang; L.S. Zhang; Q.J. Zhang; S.Q. Zhang; X.M. Zhang; X.Y. Zhang; Yiyun Zhang; Y.J. Zhang; Y.Y. Zhang; Z.P. Zhang; Z.Q. Zhang; D.X. Zhao; J.B. Zhao; J.W. Zhao; P.P. Zhao; W.R. Zhao; X.J. Zhao; Y.B. Zhao; Z.G. Zhao; H.Q. Zheng; J.P. Zheng; L.S. Zheng; Z.P. Zheng; X.C. Zhong; B.Q. Zhou; G.M. Zhou; L. Zhou; N.F. Zhou; K.J. Zhu; Q.M. Zhu; Yingchun Zhu; Y.C. Zhu; Y.S. Zhu; Z.A. Zhu; B.A. Zhuang; B.S. Zou
• Keywords: Nuclear and High Energy Physics; 0103 physical sciences; 01 natural sciences; 7. Clean energy; High Energy Physics - Experiment

Comment: 6 pages, 2 figures, RevTex4, Submitted to Phys.Lett.B<br/>The process J/\psi --> p \bar{p} is studied using 57.7 X 10^6 J/\psi events collected with the BESII detector at the Beijing Electron Positron Collider. The branching ratio is determined to be Br(J/\psi --> p \bar{p})=(2.26 +- 0.01 +- 0.14) X 10^{-3}, and the angular distribution is well described by \frac{dN}{d cos\theta_p}=1+\alpha\cos^2\theta_p with \alpha = 0.676 +- 0.036 +- 0.042, where \theta_p is the angle between the proton and beam directions. The value of \alpha obtained is in good agreement with the predictions of first-order QCD.<br/>