Title: Unintegrated Gluon Distributions at Small-x
Description: The study of strong interactions at very high energies has prompted a large interest in the small-x regime of quantum chromodynamics where partons carry a small fraction of the momentum of their parent hadrons. In this regime gluon occupation numbers are believed to be very high leading to saturation of the corresponding parton densities. This thesis is intended to explore the validity of factorization approaches in the small-x regime and establish a relation with partonic interpretations when possible. Two fundamental unintegrated (transverse momentum dependent) gluon distributions are proposed as fundamental building blocks to describe all processes sensitive to the small-x regime which admit a factorized description. Single-particle production processes and two-particle production processes are studied in asymmetric collisions of a dilute probe scattering from a dense target and it is shown that it is possible to recover factorized expression in a particular kinematical limit.