Quark spin-orbit correlations in the pion in a light-cone quark model

We study the correlation between the quark spin and orbital angular momentum inside the pion meson. Similar to the case inside the nucleon, the longitudinal spin-orbit correlation Cq/pi z in the pion meson can be expressed in terms of the corresponding generalized parton distributions (GPDs) and generalized transverse momentum distributions (GTMDs). This provides new information about the spin structure of the pion. Using the wave functions of the pion in the light-cone quark model and the overlap representation for GPDs and GTMDs, we present the analytical results for the quark longitudinal spin-orbit correlation. We find that the GPD approach and the GTMD approach lead to the same results. The numerical results are also obtained, showing that the correlation in the pion is antialigned. In addition, we compare Cq/pi z from the GPD approach and the GTMD approach, with x and the transverse momentum kT unintegrated.