Dihadron fragmentation functions in the quark-jet model: Transversely polarized quarks

TL;DR

This paper extends the quark-jet model to study transversely polarized dihadron fragmentation functions, revealing discrepancies in their definitions and completing the analysis of all leading twist DiFFs within this framework.

Contribution

It introduces a Monte Carlo approach to model polarized quark hadronization and clarifies the definitions of interference DiFFs within the quark-jet model.

Findings

Discrepancies found between different definitions of the interference DiFF $H_1^\sphericalangle$

Completed the analysis of all four leading twist DiFFs for unpolarized hadron pairs

Provided Fourier cosine moments of the DiFFs using Monte Carlo simulations

Abstract

Within the most recent extension of the quark-jet hadronization framework, we explore the transverse-polarization-dependent dihadron fragmentation functions (DiFFs) $H_1^\sphericalangle$ and $H_1^\perp$ of a quark into $\pi^+\pi^-$ pairs. Monte Carlo (MC) simulations are employed to model polarized quark hadronization and calculate the corresponding number densities. These, in turn, are used to extract the Fourier cosine moments of the DiFFs $H_1^\sphericalangle$ and $H_1^\perp$. A notable finding is that there are previously unnoticed apparent discrepancies between the definitions of the so-called interference DiFF (IFF) $H_1^\sphericalangle$, entering the cross sections for two-hadron semi-inclusive electroproduction, and those involved in the production of two pairs of hadrons from back-to-back jets in electron-positron annihilation. This manuscript completes the studies of all four leading twist DiFFs for unpolarized hadron pairs within the quark-jet framework, following our previous work on the helicity-dependent DiFF $G_1^\perp$.