We study the $\cos2\phi$ azimuthal asymmetry in doubly longitudinally polarized proton-proton Drell-Yan collisions within the transverse momentum dependent factorization framework. The asymmetry arises from the convolution of the longitudinal transversity distribution $h_{ 1L}^{ \perp}$ for both protons. Using the Bacchetta-Delcarro-Pisano-Radici-Signori parametrization for the nonperturbative Sudakov form factor and the Wandzura-Wilczek approximation for the collinear $h_{ 1L}^{ \perp}$, we predict the double spin asymmetry $A_{ LL}^{ \cos2\phi}$ at RHIC and NICA kinematics. Our results demonstrate sensitivity to sea quark distributions, with the asymmetry reaching up to $25\%$ for maximal sea quark contributions. These predictions highlight the potential of polarized Drell-Yan measurements to probe sea quark dynamics and advance our understanding of nucleon structure.
Categories: hep-ph