The $\sin 2\varphi$ azimuthal asymmetry in single longitudinally polarized $\pi N$ Drell-Yan process

Abstract

We study the $\sin 2\varphi$ azimuthal asymmetry in the $\pi N$ Drell-Yan process, when the nucleon is longitudinally polarized. The asymmetry is contributed by the combination of the Boer-Mulders function and the longitudinal transversity distribution function. We consider the Drell-Yan processes by ${\pi }^{\pm }$ beams colliding on the proton and deuteron targets, respectively. We calculate the $\sin 2\varphi$ azimuthal asymmetries in these processes using the Boer-Mulders function and the longitudinal transversity from spectator models. We show that the study on single polarized $\pi N$ Drell-Yan processes can not only give the information on the new 3-dimensional parton distribution functions in momentum space, but also shed light on the chiral-odd structure of the longitudinally polarized nucleon.

Comments: 7 pages, 3 figures. Final version for publication in PRD