Radiatively generated parton distributions of real and virtual photons
Radiatively generated parton distributions of real and virtual photons
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DOI：
10.1103/physrevd.60.054019
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发表时间：
1999-03
影响因子：
5
通讯作者：
M. Gluck;E. Reya;I. Schienbein
中科院分区：
文献类型：
--
作者：
M. Gluck;E. Reya;I. Schienbein
真实 ${(P}^{2}=0)$ 和虚拟 ${(P}^{2}\ensuremath{\ne}0)$ 横向光子 $\ensuremath{\gamma}{(P}^{2})$ 的部分子含量以微扰点状和非微扰强子 (VMD) 分量表示，采用最近更新的π介子和质子部分子分布。由此产生的无参数且扰动稳定的 LO 和 NLO 部分子密度 ${f}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2})$ 在 ${P}^{2}$ 中是平滑的，并且每当在尺度上探测 $\ensuremath{\gamma}{(P}^{2})$ 时都适用于所有 ${P}^{2}g~0$ ${Q}^{2}\ensuremath{\gg}{P}^{2}$ 其中横向光子也主导物理相关横截面。给出了结构函数 ${F}_{2}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2})$ 和 ${f}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2}),$ 的预测，并与真实光子的所有相关数据以及从 DIS 提取的虚拟光子的最新数据进行比较$\mathrm{ep}$ dijet 事件。我们对 LO 和 NLO 中的真实光子以及 LO 中的虚拟光子提出了我们预测的部分子分布的简单分析参数化，在足够的精度内，也可以在 NLO-QCD 中使用。
The parton content of real ${(P}^{2}=0)$ and virtual ${(P}^{2}\ensuremath{\ne}0)$ transverse photons $\ensuremath{\gamma}{(P}^{2})$ is expressed in terms of perturbative pointlike and nonperturbative hadronic (VMD) components, employing recently updated parton distributions of pions and protons. The resulting parameter-free and perturbatively stable LO and NLO parton densities ${f}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2})$ are smooth in ${P}^{2}$ and apply to all ${P}^{2}g~0$ whenever $\ensuremath{\gamma}{(P}^{2})$ is probed at scales ${Q}^{2}\ensuremath{\gg}{P}^{2}$ where transverse photons also dominate physically relevant cross sections. Predictions are given for the structure function ${F}_{2}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2})$ and ${f}^{\ensuremath{\gamma}{(P}^{2})}{(x,Q}^{2}),$ and are compared with all relevant data for real photons as well as with recent data for virtual photons as extracted from DIS $\mathrm{ep}$ dijet events. Simple analytic parametrizations of our predicted parton distributions are presented for the real photon in LO and NLO, and for the virtual photon in LO which, within sufficient accuracy, may be also used in NLO-QCD.