论文标题
全息光前QCD中颜色透明度的发作
Onset of color transparency in holographic light-front QCD
论文作者
论文摘要
强子的颜色透明度（CT），随着核中的吸收降低而传播，是QCD（量子染色体动力学）的基本特性，反映了其内部结构和在高横向动量下产生$ q $时的内部结构和有效尺寸。在许多实验中已经确认了CT，例如半独立的硬电源，$ e a \ to e'πx$对于$ q^2> 3〜 {\ rm gev}^2 $。但是，最近对碳$ e \，{\ rm c} \ to e'p x $中的质子进行了质子测量的近期JLAB（杰斐逊实验室）测量，其中$ x $代表所有生产的最终状态的包容性，未能在$ q^2 $ q^2 $ q^2 $ q ev $^$^$^2 $中观察到CT。在本文中，CT的开始是通过比较使用HADRONIC横截面的$ Q^2 $依赖性，用于使用来自Holotaphic Light-Front QCD的通用Parton分布的小色彩单词配置的初始形成。对于CT的开始，发现了对强子扭曲的关键依赖性$τ$，即强子成分的数量，没有核培养基的显着影响。这种作用可以解释JLAB实验的当前运动学范围内质子CT的不存在。预计质子具有“两阶段”的颜色透明度，而CT的发作对于自旋旋转（twist-3，$τ= 3 $）的DIRAC形式不同，并且Spin-Flip Pauli（Twist-4）形式的$ q^2 $发作较高。相比之下，由于其Pauli形式的主导地位，预计中子具有“单阶段”的颜色透明度，其发作为较高$ q^2 $。该模型还预测，低能能对夸克电流耦合与强子的风味有很强的依赖性。
The color transparency (CT) of a hadron, propagating with reduced absorption in a nucleus, is a fundamental property of QCD (quantum chromodynamics) reflecting its internal structure and effective size when it is produced at high transverse momentum, $Q$. CT has been confirmed in many experiments, such as semi-exclusive hard electroproduction, $e A \to e' πX$ for mesons produced at $Q^2 > 3 ~ {\rm GeV}^2$. However, a recent JLab (Jefferson Laboratory) measurement for a proton electroproduced in carbon $e\, {\rm C}\to e' p X$, where $X$ stands for the inclusive sum of all produced final states, fails to observe CT at $Q^2$ up to 14.2 GeV$^2$. In this paper, the onset of CT is determined by comparing the $Q^2$-dependence of the hadronic cross sections for the initial formation of a small color-singlet configuration using the generalized parton distributions from holographic light-front QCD. A critical dependence on the hadron's twist, $τ$, the number of hadron constituents, is found for the onset of CT, with no significant effects from the nuclear medium. This effect can explain the absence of proton CT in the present kinematic range of the JLab experiment. The proton is predicted to have a "two-stage" color transparency with the onset of CT differing for the spin-conserving (twist-3, $τ=3$) Dirac form factor with a higher onset in $Q^2$ for the spin-flip Pauli (twist-4) form factor. In contrast, the neutron is predicted to have a "one-stage" color transparency with the onset at higher $Q^2$ because of the dominance of its Pauli form factor. The model also predicts a strong dependence at low energies on the flavor of the quark current coupling to the hadron.
