Parton Recombination and the Phenomenology of GLR Based Nonlinear Evolution Equations

In the realm of quantum chromodynamics (QCD), the understanding of parton recombination phenomena plays a pivotal role in elucidating the behavior of strongly interacting systems and in the prediction of various standard model processes at accelerators such as LHC and RHIC. This chapter delves into the intricate interplay between parton recombination, and the phenomenology derived from the Gribov-Levin-Ryskin (GLR) based nonlinear evolution equations.

Beginning with a comprehensive overview of parton distribution functions (PDFs), we discuss the linear evolution equation known as Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) which is used to study the evolution of parton distributions. This establishes the theoretical groundwork necessary for delving into the structure of hadrons. Then, we discuss the recombination phenomenon, by incorporating which modifies the DGLAP equation into a nonlinear evolution equation known as the GLR equation. Drawing upon the GLR-based nonlinear evolution equations, we elucidate their significance in modeling the non-linear saturation effects using the solutions obtained from these GLR-based evolution equations at the regime of high parton densities.

Furthermore, we discuss the phenomenological applications of parton recombination effects on the evolution of parton distribution functions (PDFs) within the context of heavy-ion collisions and deep inelastic scattering experiments. By analyzing experimental data and theoretical predictions, we assess the validity of GLR-based approaches in capturing the intricate dynamics of Parton evolution in various energy regimes.

Conclusively, this chapter offers a comprehensive synthesis of parton recombination phenomena, emphasizing their significance within the framework of GLR-based nonlinear evolution equations.