Ratios of helicity amplitudes for hard exclusive _0 electroproduction on transversely polarized protons
2017 December 31
2018 January 16
The HERMES experiment collected a wealth of deep-inelastic scattering data using the 27.6 GeV polarized lepton beam at HERA and various pure gas targets, both unpolarized and polarized. This allowed for a series of diverse measurements. Among them are measurements of hard exclusive meson production, which provide information on generalized parton distributions (GPDs), in a complementary way to, e.g., deeply virtual Compton scattering. Access to these GPDs is possible through the measurement of helicity-amplitude ratios. Helicity-amplitude ratios from exclusive ρ0 production on transversely polarized hydrogen are presented and discussed as well as compared to the theoretical ‘GK’ model.