A new modified Altarelli-Parisi evolution equation with parton recombination in proton

TL;DR

This paper introduces a modified Altarelli-Parisi evolution equation incorporating parton recombination effects, valid across all x regions, and compares it with the Gribov-Levin-Ryskin equation to enhance understanding of parton dynamics.

Contribution

It presents a new nonlinear evolution equation with parton recombination terms, extending previous models to the entire x range and including the $GG\to q\bar q$ process.

Findings

Coefficients of nonlinear terms determined in leading logarithmic approximation

Equation valid across the whole x region

Comparison with Gribov-Levin-Ryskin equation provided

Abstract

The coefficients of the nonlinear terms in a modified Altarelli-Parisi evolution equation with parton recombination are determined in the leading logarithmic ($Q^2$) approximation. The results are valid in the whole $x$ region and contain the translation $GG\to q\bar q$, which is inhibited in the double leading logarithmic approximation. The comparisons of the new evolution equation with the Gribov-Levin-Ryskin equation are presented.