# Collinear matching for Sivers function at next-to-leading order

## TL;DR

This paper calculates the next-to-leading order matching coefficient for the Sivers function using light-cone operator product expansion, providing detailed methodology and advancing understanding of TMD operators at twist-3.

## Contribution

It introduces a novel NLO calculation of the Sivers function's matching coefficient via light-cone OPE in the background-field approach.

## Key findings

- Derived the NLO matching coefficient for the Sivers function.
- Presented detailed methodology for twist-3 TMD operator expansion.
- Enhanced theoretical understanding of TMD factorization at higher orders.

## Abstract

We evaluate the light-cone operator product expansion for the unpolarized transverse momentum dependent (TMD) operator in the background-field technique up twist-3 inclusively. The next-to-leading order (NLO) matching coefficient for the Sivers function is derived. The method, as well as many details of the calculation, are presented.