Azimuthal asymmetries in production of charged hadrons by high energy muons on polarized deuterium targets

TL;DR

This study investigates azimuthal asymmetries in charged hadron production by high-energy muons on polarized deuterium, finding no dependence on azimuthal angle and exploring potential contributions from various parton functions.

Contribution

It provides the first detailed analysis of azimuthal asymmetries in semi-inclusive charged hadron production on polarized deuterium using COMPASS data, considering multiple modulation functions.

Findings

Asymmetries are independent of azimuthal angle.

Results are consistent with the ratio g_1^d(x)/f_1^d(x).

Amplitude dependencies on x, z, and p_h^T are analyzed.

Abstract

Search for azimuthal asymmetries in semi-inclusive production of charged hadrons by 160 GeV muons on the longitudinally polarized deuterium target, has been performed using the 2002- 2004 COMPASS data. The observed asymmetries integrated over the kinematical variables do not depend on the azimuthal angle of produced hadrons and are consistent with the ratio $g_1^d(x)/f_1^d(x)$. The asymmetries are parameterized taking into account possible contributions from different parton distribution functions and parton fragmentation functions depending on the transverse spin of quarks.They can be modulated (either/or/and) with $\sin(\phi), \sin(2\phi), \sin(3\phi)$ and $\cos(\phi)$. The $x$-, $z$- and $p_h^T$-dependencies of these amplitudes are studied.