Polarized \(J/\psi\) production in semi-inclusive DIS at large \(Q^2\): Comparing quark fragmentation and photon-gluon fusion

We compare the relative importance of different mechanisms for polarized \(J/\psi\) production in semi-inclusive deep inelastic scattering processes at large \(Q^2\). The transverse momentum dependent (TMD) factorization framework and nonrelativistic quantum chromodynamics are used to study the leading contributions from light quark fragmentation to polarized \(J/\psi\), and compared to direct production via photon-gluon fusion, which can proceed through color-singlet as well as color-octet mechanisms. We identify kinematic regimes where light quark fragmentation dominates, allowing for the extraction of the \(^3S_1^{[8]}\) matrix element, as well as regimes where photon gluon fusion dominates, suggesting that the gluon TMD parton distribution function can be probed.