We summarize basic theoretical ideas which let to the observation of the short-range correlations (SRC) in nuclei using hard probes and outline directions for probing quark-gluon structure of SRCs. Implications of the observations of color transparency for processes involving pions are reviewed. Open questions and directions for further studies of color transparency phenomena using hadronic projectiles are presented using as an example the PANDA detector at FAIR.
Color transparency occurs if a small-sized wave packet, formed in a high momentum transfer process, escapes the nucleus before expanding. The time required for the expansion depends on the masses of the baryonic components of the wave packet. Measured proton diffractive dissociation and electron deep inelastic scattering cross sections are used to examine and severely constrain the relevant masses. These constraints allow significant color transparency effects to occur at experimentally accessible momentum transfers.
Possible evidence for color transparency from dijet production with large rapidity gaps in $γp$ scattering at HERA and how to test it in $γp, γA$ scattering
Evidence for Observation of Color Transparency in pa Collisions Using Global Fit and Scaling Law Analysis
本文综述了一种新的系统的色透明实验数据分析方法及其在质子核散射实验中的应用。该方法直接从数据中提取硬散射率以及质子穿过核的存活概率。该方法需要在一个有效的核子-核子截面方面的核衰减建模。我们可以通过引入一个新的标度律分析程序，可以产生相当多的信息，很少的理论输入，最大限度地减少这种模型的依赖。有了足够的数据，生存概率的函数形式以及硬散射可以提取没有任何理论建模。Carroll {\it et al}的BNL数据分析显示了观察颜色透明度的明确证据。
Generalized Parton Distributions and Color Transparency
我们研究了广义部分子分布在碰撞参量空间中的结构，目的是确定小横向分离分量在夸克波函数中的大小和作用。分析了横向动量分量与横向分离的关系。具有大的横向动量分量的波函数可以同时再现狄拉克形状因子在大动量转移时的行为和Bjorken x -> 1时的深部非弹性结构函数的行为。然而，大动量分量的存在并不能保证在大x时小横向距离占优势。我们认为，测量强子在核介质中的衰减，或开始的颜色透明的实验，可以提供一个替代的信息来源广义部分子分布，通过映射出的行为的横向分量的波函数。
We propose to study the onset of color transparency in hard exclusive reactions in the backward regime. Guided by the encouraging JLab results on backward pion and omega electro-production data at moderate Q^2, which may be interpreted as the signal of an early scaling regime where the scattering amplitude factorizes in a hard coefficient function convoluted with nucleon to meson transition distribution amplitudes, we show that the study of these channels on nuclear targets opens a new opportunity to test the appearance of nuclear color transparency for a fast moving nucleon.
In the current paper, we argue that the ground state of a hadron contains a significant perturbative quantum chromodynamics (pQCD) core as the result of color gauge invariance and of the values of chiral and gluon vacuum condensates. The evaluation within the method of dispersion sum rules (DSR) of the vacuum matrix elements of the correlator of local currents with the proper quantum numbers leads to the value of the radius of the pQCD core of a nucleon of about 0.4--0.5 fm. The selection of the initial and final states allows to select processes in which the pQCD core of the projectile gives …
A recent experiment [{\bf Phys. Rev. Lett. 126,082301 (2021)}] used the $(e,e'p)$ reaction on $^{12}$C to search for the effects of color transparency (the absence of final state interactions). Color transparency was said to be ruled out. The ability to observe the effects of color transparency depends on the ability of a putative point-like-configuration (PLC), formed in a high-momentum transfer coherent reaction, to escape the nucleus without expanding its size. We study the expansion aspect of color transparency using superconformal baryon-meson symmetry and light-front holographic QCD. A n…
40 years after its introduction, the phenomenon of color transparency remains a domain of controversial interpretations of experimental data. We review present evidence for or against its manifestation in various exclusive hard scattering reactions. The nuclear transparency experiments reveal whether short distance processes dominate a scattering amplitude at some given kinematical point. We plead for a new round of nuclear transparency measurements in a variety of experimental set-ups, including near-forward exclusive reactions related to generalized parton distribution (GPD) physics and near…
Color transparency, the reduction of initial- or final-state interactions in coherent nuclear processes, is a natural prediction of QCD provided that small-sized or point-like configurations (PLCs) are responsible for high-momentum transfer, high-energy, semi-exclusive processes. I use the FMS criteria for the existence of PLCs to show that the wave functions of light front holographic QCD, as currently formulated, do not contain a PLC.
Non-universality of color transparency onset in pion and kaon electroproduction
Center for Exotic Nuclear Studies, Institute for Basic Science（基础科学研究所奇异核研究中心）；Research Institute of Basic Science, Korea Aerospace University（韩国航空大学基础科学研究所）；Department of Physics and Engineering Physics, Yonsei University（延世大学物理与工程物理系）
Naive parton picture for kaon color transparency in $A(e,e'K^+)$
Research Institute of Basic Science, Korea Aerospace University（韩国航空航天大学基础科学研究所）；Department of Physics and Engineering Physics, Yonsei University（延世大学物理与工程物理系）；Center for Exotic Nuclear Studies, Institute for Basic Science（基础科学研究院奇异核研究中心）
