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.
@article{arxiv.hep-ex/0402034,
title = {Measurements of J/psi --> p \bar{p}},
author = {J. Z. Bai},
journal= {arXiv preprint arXiv:hep-ex/0402034},
year = {2008}
}
Comments
6 pages, 2 figures, RevTex4, Submitted to Phys.Lett.B