Single inclusive forward hadron production at next-to-leading order

TL;DR

This paper addresses the issue of negative cross sections in next-to-leading order calculations of forward hadron production by identifying the oversubtraction problem and proposing a new kinematic restriction method within the Color Glass Condensate framework.

Contribution

It introduces a novel approach to implement kinematic restrictions that corrects the oversubtraction issue in NLO calculations of hadron production.

Findings

Identified oversubtraction of rapidity divergence causes negative cross sections.

Proposed a new kinematic restriction method to fix the problem.

Improved the theoretical consistency of NLO calculations in the CGC formalism.

Abstract

We discuss single inclusive hadron production from a high energy quark scattering off a strong target color field in the Color Glass Condensate formalism. Recent calculations of this process at the next-to-leading order accuracy have led to negative cross sections at large transverse momenta. We identify the origin of this problem as an oversubtraction of the rapidity divergence into the Balitsky-Kovchegov evolution equation for the target. We propose a new way to implement the kinematical restriction on the emitted gluons to overcome this difficulty.