Ratios of helicity amplitudes for exclusive ${\rho }^0$ electroproduction on transversely polarized protons

The HERMES Collaboration, A. Airapetian, N. Akopov +74

Exclusive ${\rho }^0$-meson electroproduction is studied by the HERMES experiment, using the 27.6 GeV longitudinally polarized electron/positron beam of HERA and a transversely polarized…