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

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.

Comments: 26 pages, 12 figures. The complete derivations of the parton recombination functions are presented in a new Appendix