Descrição da dinâmica das interações fortes a altas energias além da ordem dominante no regime de saturação

Abstract

The high energy (small-x) regime of quantum chromodynamics (QCD) has been under intense investigation in electron-hadron and hadron-hadron collisions. In this regime, saturation effects associated with the high gluonic density are expected to modify the QCD dynamics, implying the presence of non-linear effects that reduce the growth of the gluon distribution at small-x. The description of the saturation region is given by the Color Glass Condensate (CGC), which is an effective theory for the high density regime. The CGC theory implies that the dipole-hadron scattering amplitude satisfies the Balitisky-Kovchegov (BK) equation in the mean-field approximation, which allows us to estimate the contribution of the non-linear effects. In recent years, several authors have obtained the numerical solution of the BK equation at leading order in the full kinematical range, as well its analytical solutions in the linear and saturation regimes. On the other hand, the description of the next-to-leading order (NLO) corrections for the BK equation is still a theme of intense debate in the literature. Currently, there are different treatments for the NLO corrections and distinct prescriptions for the hard scale of the running coupling constant. In this dissertation, we focus on the derivation of the solutions of the BK equation in the saturation regime considering these distinct treatments and prescriptions. Then, the solutions for the dipole-hadron scattering amplitude will be derived in detail and a comprehensive comparison between them will be presented for the first time.