A phenomenological study on the $\cos\phi_h$ azimuthal asymmetry in double longitudinally Polarized SIDIS

TL;DR

This study investigates the $ ext{cos}\phi_h$ azimuthal asymmetry in double polarized SIDIS, emphasizing the impact of twist-3 transverse momentum dependent distributions and providing predictions for experimental measurements.

Contribution

It introduces a phenomenological analysis of twist-3 effects on azimuthal asymmetry using spectator models, predicting positive asymmetries for various pions at existing experimental facilities.

Findings

Asymmetries are positive for all pions studied.

$g_L^ot$ dominates the asymmetry contribution.

Predicted asymmetries are accessible at CLAS and HERMES.

Abstract

We study the $\cos{\phi_h}$ azimuthal asymmetry in double polarized semi-inclusive pion production by considering dynamical twist-3 effects. In particular, we evaluate the role of the transverse momentum dependent distributions $e_L(x, k_T^2)$ and $g_L^\perp(x, k_T^2)$ on the asymmetry. Using two different sets of spectator model results for these distributions, we predict the $\cos{\phi_h}$ asymmetry of $\pi^+$, $\pi^-$, and $\pi^0$ at the kinematic configuration available at CLAS, HERMES and COMPASS. Our estimates show that the asymmetries are positive for all the pions and could be accessed by CLAS and HERMES. We also find that $g_L^\perp$ gives the dominant contribution to the $\cos\phi_h$ asymmetry, while the contribution of $e_L$ is almost negligible.