Date of Award
Doctor of Philosophy
Physics and Astronomy
Protons and neutrons are known to be the building blocks of matter, and also known to be the bound states of quarks and gluons - the partons, whose dynamics is best described by Quantum Chromodynamics (QCD). Perturbative QCD has been very successful in interpreting and predicting high-energy hadronic scattering processes by factorizing the leading contribution to the physical cross sections into a convolution of the perturbatively calculable short-distance part and the universal long-distance parton distribution functions (PDFs) of colliding hadrons. Besides testing QCD dynamics at the short-distance, these cross sections also probe partonic structure inside a colliding hadron via PDFs, which are often interpreted as the probability densities of finding a parton inside a hadron with a given longitudinal momentum fraction.
In this thesis I discuss the possibilities to explore the rich partonic dynamics inside a hadron or a large nucleus beyond the probability distributions. I will first explain why a difference of two transverse-spin dependent cross sections (or the measurement of the single transverse-spin asymmetry) can directly probe a set of new three-parton correlation functions. These correlation functions provide the first direct information on quantum correlation between quarks and gluons inside a polarized hadron. I will describe the basic formalism and the experimental measurements of these correlation functions. I will present the first derivation of evolution equations (or renormalization group equations) for these correlation functions. I will then discuss how to use the nuclear dependence of high energy nuclear collisions to extract the information on four-parton correlations inside a large nucleus or a nuclear medium. The measurements of the spin asymmetry and the anomalous nuclear dependence provide us new opportunities to explore the QCD dynamics and hadron structure beyond the parton probability distributions.
Kang, Zhongbo, "QCD quantum correlation and multi-parton dynamics" (2009). Graduate Theses and Dissertations. Paper 10652.