%0 Journal Article %T Study on $N\bar{N}$ $S$-wave Elastic Cross Section and Possible Bound States Within a Constituent Quark Model %A Hourong Pang %A Jialun Ping %A Fan Wang %J Physics %D 2007 %I arXiv %R 10.1088/0256-307X/25/9/027 %X In the framework of a chiral constituent quark model, considering the contributions of $\pi$ annihilation and one-gluon annihilation, the proton-antiproton $S$-wave elastic scattering cross section experimental data can be reproduced by adjusting properly one-gluon annihilation coupling constant. Meanwhile, using the fixed model parameter, we do a dynamical calculation for all possible $S$-wave nucleon-antinucleon states, the results show that, there is no $S$-wave bound state as indicated by a strong enhancement at threshold of $p\bar{p}$ in $J/\psi$ and $B$ decays. %U http://arxiv.org/abs/0712.4376v1