2-soft-gluon exchange and factorization breaking

TL;DR

This paper demonstrates through explicit calculations that standard k_T-factorization breaks down for high transverse momentum hadron production in unpolarized hadron-hadron collisions, extending previous counterexamples to higher order gluon exchanges.

Contribution

It provides a higher-order calculational proof that k_T-factorization fails in certain high-energy hadron collision processes, challenging its universality.

Findings

Standard k_T-factorization fails at higher order gluon exchanges.

Explicit calculations confirm breakdown for unpolarized high-p_T hadron production.

Extends previous counterexamples to demonstrate factorization breaking.

Abstract

A previous counterexample to disprove k_T-factorization for H_1+H_2 --> H_3+H_4+X is extended calculationally to one higher order in gluon exchange. The result is that, by explicit calculation, standard k_T-factorization fails for the unpolarized cross-section for the production of hadrons of high transverse momentum in hadron-hadron collisions.