Double-spin asymmetry $A_{LT}$ in open charm production

Yoshitaka Hatta, Koichi Kanazawa, Shinsuke Yoshida

Published 2013-05-30, updated 2013-09-09Version 2

In the collinear twist-three approach, we calculate for the first time the gluon contribution to double (longitudinal-transverse) spin asymmetry A_{LT} for open charm production in proton-proton collisions measurable at RHIC. Utilizing the Ward-Takahashi identity for the non-pole part of the hard scattering amplitude, we derive a factorized, gauge invariant formula for the asymmetry. The result may be combined with the previous studies of single-spin asymmetry in the same channel and allows for a systematic analysis of three-gluon correlations inside a transversely polarized nucleon.