Rho-0 Meson Helicity Amplitude Ratios at HERMES

Abstract

The study of ρ0 meson helicity amplitude ratios at HERMES shows that the amplitude hierarchy expected from pQCD is confirmed. The contribution of Unnatural Parity Exchange in the production of ρ0 mesons is significant at HERMES kinematics and there is a large phase-difference in the leading F11 and F01 amplitudes. The kinematic dependences of the amplitude ratios only sometimes follow theory-based expectations.

4 pages, 3 figures, prepared for DIS 2011