The difference cross sections of unpolarized SIDIS with transverse momentum dependence

TL;DR

This paper extends a model-independent approach to analyze difference cross sections in unpolarized SIDIS with transverse momentum dependence, enabling separate determination of TMD valence quark densities and fragmentation functions.

Contribution

It introduces a method to express difference cross sections with transverse momentum dependence solely in terms of valence TMD densities and fragmentation functions, including Boer-Mulders and Collins functions.

Findings

Expressed difference cross sections in terms of valence TMD densities and FFs.

Provided a way to determine flavor dependence of quark transverse momentum.

Identified independent measurements for valence quark TMD sums.

Abstract

Previously we showed that, based only on C and SU(2) invariance, the difference cross sections of hadrons with opposite charge in SIDIS e+N\to l+h+X is expressed solely in terms of the valence-quark densities and certain non-singlet combinations of FFs. This allowed to determine these quantities in a model independent way. Now we extend this approach to processes when the transverse momentum of the final hadron is measured as well. We show that the difference cross sections of unpolarized SIDIS on proton and deuterium targets, d\s_N^{h^+-h^-}, d\s_N^{\pi^+-\pi^-} and d\s_N^{K^+-K^-}, are expressed solely in terms of the TMD unpolarized valence quark densities and FFs, and the valence-quark Boer-Mulders and Collins functions. This allows to determine them separately and study flavour dependence of the quark transverse momentum. Measurements on deuterium target, d\s_d^{h^+-h^-}, d\s_d^{\pi^+-\pi^-} and d\s_d^{K^+-K^-}, provide 3 independent measurements for the sum of the TMD valence quark densities and Boer-Mulders functions: (u_{1,V}+d_{1,V}) and (h_{1,uV}^\perp + h_{1,dV}^\perp).