Double spin asymmetry in dihadron production in SIDIS off the longitudinally polarized nucleon target

Understand

In this paper we study the double longitudinal spin asymmetry of dihadron production in semi-inclusive deep inelastic scattering (SIDIS).

• We calculate a unknown twist-3 dihadron fragmentation function $\widetilde{D}^\sphericalangle$ within a spectator model which has been used successfully in describing the dihadron production in both the unpolarized and the single polarized processes.
• The collinear picture, in which the transverse momentum of the final state hadron pair is integrated out, has been considered.
• The $\cos\phi_R$ azimuthal asymmetry arises from the coupling $e_L H_1^\sphericalangle$ and the coupling $g_1 \widetilde{D}^\sphericalangle$ is studied.