Mass distributions for the $\pi \rho$ final state in the reaction $\pi N\to \pi \rho N$ are calculated from a Regge-pole-exchange model. Compared with the results of the Drell-Deck-type models, significantly increased $\pi \rho$ mass peaking in the $A_1$ region is predicted; calculated widths are consistent with results of recent experiments on the $A_1$.

• Received 29 September 1967

DOI:https://doi.org/10.1103/PhysRev.166.1525