论文标题
亲束和光子束引发向后炭或轻顿对生产
Pion and photon beam initiated backward charmonium or lepton pair production
论文作者
论文摘要
可以研究由小型mandelstam变量$ -U $指定的近后背部运动学方案中发起的硬性独家反应，以访问pion-to-nucleon和光子到核核转变分布振幅（TDAS）。检查按照TDA的PION和光子诱导反应的共线性分解描述的有效性，可以测试QCD共线化方法的类似空间样和类似时间样式的TDA的普遍性。在这篇简短的综述中，我们考虑了近后退区域中一对高度虚拟Lepton对（或重型Quarkonium）的核子的独家发射和照片产生。我们首先采用了Pion-to-Nucleon TDA的简单横向通道核交换模型，以估算J-PARC运动学条件的相应横截面的大小。然后，我们通过基于接近阈值的初步结果$ j/ψ$ jlab上的jlab $ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ$ j/ψ。
Hard exclusive reactions initiated by pion or photon beams within the near-backward kinematical regime specified by the small Mandelstam variable $-u$ can be studied to access pion-to-nucleon and photon-to-nucleon Transition Distribution Amplitudes (TDAs). Checking the validity of collinear factorized description of pion and photon induced reactions in terms of TDAs allows to test the universality of TDAs between the space-like and time-like regimes that is the indispensable feature of the QCD collinear factorization approach. In this short review we consider the exclusive pion- and photo-production off nucleon of a highly virtual lepton pair (or heavy quarkonium) in the near-backward region. We first employ a simplistic cross channel nucleon exchange model of pion-to-nucleon TDAs to estimate the magnitude of the corresponding cross sections for the kinematical conditions of J-PARC. We then illustrate the flexibility of our approach by building a two parameter model for the photon-to-nucleon TDAs based on preliminary results for near threshold $J/ψ$ photoproduction at JLab and provide our estimates for near-backward $J/ψ$ photoproduction and Timelike Compton Scattering cross sections for the kinematical conditions of JLab and of future EIC and EicC.
