ρ介子类时形状因子领头扭度的次领头阶研究

Time-like Rho Meson Electromagnetic Form Factors with the Next-to-leading-order Twist-2 Contribution

介子形状因子的研究对了解介子内部结构和相关动力学区域具有非常重要的意义。采用基于因子化理论的微扰QCD(PQCD)因子化方法,考虑湮灭过程e^(+)e^(-)→ρ^(+)ρ^(-)中ρ介子类时形状因子领头扭度的次领头阶贡献。利用解析延拓的方法直接将类空形状因子计算得到类时形状因子的解析修正函数,并做数值计算。结合大动量区域下ρ介子类时形状因子领头扭度的领头阶和次领头阶的贡献随Q^(2)的变化曲线,发现考虑次领头阶的修正后,形状因子会有20%的涨幅。通过计算得出了湮灭过程e^(+)e^(-)→ρ^(+)ρ^(-)在s=112GeV^(2)时的散射截面值,并与实验数据做比较。

The study of meson form factor is of great significance to understand the internal structureof mesons and the dynamics of the strong interaction and the transition between the low-enery and per-turbative QCD domains.We calculated the rho meson time-like electromagnetic form factors with thenext-to-leading-order twist-2 contribution inkTfactorization approach for the annihilation processe^(+)e^(-)→ρ^(+)ρ^(-).The rho meson time-like electromagnetic meson form factors can be obtained by usingcrossing symmetry between positive and negative energy axes through the space-like form factors.Itshows that the behavior of the absolute value for rho meson time-like form factor with the leading-or-der contribution and the next-to-leading-order contribution as a function of Q^(2)in large momentumtransfer region.A 20%increase was found after accounting for the next-to-leading-order correction.The scattering cross sections of the annihilation process e^(+)e^(-)→ρ^(+)ρ^(-)at s=112Ge V^(2)were calculated andalso compared with the experimental data.