New pole contribution to $P_{h\perp}$-weighted single-transverse spin asymmetry in semi-inclusive deep inelastic scattering

TL;DR

This paper introduces a new hard pole contribution to the $P_{hot}$-weighted single-transverse spin asymmetry in semi-inclusive deep inelastic scattering, providing a complete NLO calculation and clarifying the evolution of the Qiu-Sterman function.

Contribution

It presents the first complete NLO calculation including the new hard pole contribution for the $P_{hot}$-weighted asymmetry, advancing understanding of spin asymmetry evolution.

Findings

New hard pole contribution is essential for complete evolution equations.

Performed the first full NLO calculation of the $P_{hot}$-weighted cross section.

Clarified the role of the hard pole in spin asymmetry analysis.

Abstract

In this paper, we discuss the new hard pole contribution to the $P_{h\perp}$-weighted single-transverse spin asymmetry in semi-inclusive deep inelastic scattering. We perform the complete next-to-leading order calculation of the $P_{h\perp}$-weighted cross section and show that the new hard pole contribution is required in order to obtain the complete evolution equation for the Qiu-Sterman function derived by different approaches.