Reactionπ−p→ηnat High Energies

Measurements on the reaction ${\pi }^{-}p\to \eta n$ have been carried out at Fermilab with beam energies from 20 to 200 GeV in the same experiment in which pion charge-exchange scattering was studied. The differential cross sections have a pronounced dip in the forward direction. The data can be described well by a simple Regge-pole model but the resulting $A_2$ trajectory is not degenerate with the $\rho$ trajectory extracted from the charge-exchange data.