New Predictions onπ−+p→ϱ0+n

Abstract

Assuming that the off-shell Ball amplitudes for ${\pi }^{-}+p\to {\rho }^0+n$ not only satisfy the constraints imposed by current conservation but also are smooth in the vector-meson mass, we predict all the amplitudes (including longitudinal) for ${\pi }^{-}+p\to {\rho }^0+n$ from single-pion photoproduction. Our model has no adjustable parameter, yet the calculated cross sections and density matrix are in reasonable agreement with experiment.