Revisiting the factorization theorem for $\rho {\gamma }^{\ast }\to \pi (\rho )$ at twist 3

Shan Cheng, Ya-lan Zhang, Jun Hua +2

We revisit the proof of the perturbative QCD factorization for the exclusive processes $\rho {\gamma }^{\star }\to \pi (\rho )$ at the two-parton twist-3 level. It is pointed out that the residual co…