Hard Exclusive $\phi$ meson leptoproduction at HERMES.

Mayya Golembiovskaya, Armine Rostomyan, Sergey Yaschenko & Denis Veretennikov
AThe HERMES experiment at DESY, Hamburg collected a set of data on hard exclusive vector meson ($\rho^{0}$, $\phi$ , $\omega$) leptoproduction using the 27.6 GeV self-polarized lepton beam of HERA accelerator and a longitudinally or transversely polarized or unpolarized gas target. The latest results for spin density matrix elements of exclusive $\phi$ meson production using the full statistics collected at HERMES are presented. Conclusions on the helicity amplitudes, which are related to spin density matrix...