Title: Photon or meson formation in $J/ψ$ decays into $p {\overline{p}}$ Show Chinese title

Title: 光子或介子在$J/ψ$衰变中形成 into$p {\overline{p}}$

Abstract: The measurements of the $J/\psi \rightarrow \gamma p \overline{p}$ decays by the BES Collaboration indicate an enhancement at the $p \overline{p}$ threshold which, however, is not present in the J/$\psi$ decays into $\omega p \overline{p}$ and into $\pi p \overline{p}$. Here, two processes for describing the decays $J/\psi \rightarrow \mathcal{B} p \overline{p}$ where $\mathcal{B} = \gamma, \omega$ are presented in some detail and the cases $\mathcal{B} =\phi, \pi $ are briefly touched on. The first one, applied not only to the radiative decay to reproduce the threshold peak but also to the $\omega p \overline{p}$ decay channel to improve the description of the spectrum, postulates a direct emission of the boson before the baryon pair is formed. The second process assumes that the boson $\mathcal{B}$ is emitted from the baryon pair following the $J/\psi$ decay and includes for the decays into $\gamma p \overline{p}$ a final state nucleon-antinucleon interaction based on the Paris $N \overline{N}$ potential. The reproduction of the $p \overline{p}$ distribution in the $J/\psi \rightarrow \omega p \overline{p}$ decays needs a final state interaction involving a $N(2050)\ 3/2^-$ resonance. The photon- and meson-emission rates are reproduced in a semi-quantitative way. Show Chinese abstract

Abstract: BES合作组对$J/\psi \rightarrow \gamma p \overline{p}$衰变的测量表明在$p \overline{p}$阈值处有一个增强，然而在 J/$\psi$衰变到$\omega p \overline{p}$和$\pi p \overline{p}$中却没有出现这种现象。 此处，详细介绍了描述衰变$J/\psi \rightarrow \mathcal{B} p \overline{p}$的两种过程，其中$\mathcal{B} = \gamma, \omega$是一些情况，而$\mathcal{B} =\phi, \pi $的情况则简要提及。 第一种方法不仅用于辐射衰变以再现阈值峰，还用于$\omega p \overline{p}$衰变通道以改进光谱的描述，假设玻色子在重子对形成之前直接发射。 第二个过程假设玻色子$\mathcal{B}$是在重子对的$J/\psi$衰变后发射的，并且对于衰变为$\gamma p \overline{p}$的衰变包括基于巴黎$N \overline{N}$势的末态核子-反核子相互作用。 在$J/\psi \rightarrow \omega p \overline{p}$衰变中再现$p \overline{p}$分布需要涉及$N(2050)\ 3/2^-$共振的末态相互作用。 光子和介子发射率以半定量的方式再现。