Role of pion pole in hard exlusive meson leptoproduction
We consider the pion pole contribution and transversity effects determined by the $H_T$ and $\bar E_T$ Generalized Parton Distributions (GPDs) which are essential in hard pseudoscalar and vector meson leptoproduction. We investigate spin effects in the $ω$ and $ρ^0$ reactions. It is shown that the pion pole contribution is very important in the $ω$ production. Such effects in the $ρ^0$ channel are much smaller. Our results on spin asymmetries and spin density matrix elements in these reactions were found to be in good agreement with HERMES data.
hep-ph↗