Partonic State and Single Transverse Spin Asymmetries in Semi Inclusive DIS

TL;DR

This paper verifies the transverse momentum dependent factorization for single transverse spin asymmetries in semi-inclusive DIS using partonic states, confirming the formal derivation and exploring the structure functions involved.

Contribution

It provides a direct partonic calculation to verify the TMD factorization and compares it with the formal derivation at the hadron level.

Findings

Two structure functions satisfy the TMD factorization.

Results are consistent with collinear factorization, with a different perturbative coefficient.

Confirms the validity of factorization at leading order in alpha_s.

Abstract

Using partonic states we verify the transverse momentum dependent factorization for single transverse spin asymmetries in semi inclusive DIS at leading but nontrivial order of alpha_s. The factorization has been previously derived in a formal way by using diagram expansion at hadron level. We find with our partonic results that two relevant structure functions satisfy the factorization. Our results also satisfy the collinear factorization but with the perturbative coefficient different than that derived formally.