QCD Processes in Few Nucleon Systems

Abstract

One of the important issues of Quantum Chromodynamics (QCD) - the fundamental theory of strong interaction, is the understanding of the role of the quark-gluon interactions in the processes involving nuclear targets. One direction in such studies is to explore the onset of the quark gluon degrees of freedom in nuclear dynamics. The other direction is using the nuclear targets as a `micro-labs' in studies of the QCD processes involving protons and neutrons bound in the nucleus. In the proposed research, we work in both directions considering high energy photo- and electro-production reactions involving deuteron and $^3$He nuclei. In the first half of the research, we study the high energy break-up of the $^3$He nucleus, caused by a incoming photon, into a proton-deuteron pair at the large center of mass scattering angle. The main motivation of the research is the theoretical interpretation of recent experimental data which revealed the unprecedentedly large exponent $s^{-17}$, for the energy dependence of the differential cross section. In the present research, we extend the theoretical formalism of the hard QCD rescattering model to calculate energy and angular dependences of the absolute cross section of the $\gamma ^3\text{He}\rightarrow pd$ reaction in high momentum transfer limit. The second half of the research explores the deep-inelastic scattering of a polarized electron off the polarized deuteron and $^3$He nuclei, to explore the quark-gluon structure of polarized neutron. In this work, we developed a comprehensive theoretical framework for calculation of the all relevant nuclear effects that will allow the accurate extraction of the neutron data from deep-inelastic scattering involving deuteron and $^3$He targets.