# Applications of the WW-type approximation to SIDIS

## TL;DR

This paper investigates the semi-inclusive deep-inelastic scattering (SIDIS) cross-section using WW-type approximations, simplifying the relations among TMDs and FFs, and assesses the approximation's validity with existing data.

## Contribution

It systematically applies WW-type approximations to SIDIS cross-sections up to order 1/Q^2, deriving simplified relations among TMDs and FFs, and evaluates their applicability with experimental data.

## Key findings

- WW-type approximations lead to simplified SIDIS cross-section expressions.
- Certain relations among TMDs and FFs are valid under WW-type assumptions.
- The applicability of WW-type approximations is supported by available data.

## Abstract

We explore the complete cross-section for the production of unpolarized hadrons in semi-inclusive deep-inelastic scattering up to power-suppressed $\mathcal{O}(1/Q^2)$ terms in the Wandzura-Wilczek-type (WW-type) approximation, which consists in systematically assuming that $\bar{q}gq$-correlators are much smaller than $\bar{q}q$-correlators. Under the applicability of WW-type approximations, certain relations among transverse momentum dependent parton distribution functions (TMDs) and fragmentation functions (FFs) occur which are used to approximate SIDIS cross-section in terms of a smaller subset of TMDs and FFs. We discuss the applicability of the WW-type approximations on the basis of available data.