CASE FOR STUDYING THE (PI-,PI-N) REACTION IN COINCIDENCE UNDER OPTIMUM CONDITIONS

The formalism for pion quasi-elastic scattering is reviewed with reference to the validity of certain common assumptions. It is argued that the difficulties associated with factorization are greatly reduced for knock-out from a specific nuclear state, in comparison with (for example) the first-order optical potential. Optimum conditions for a coincidence measurement are discussed. Explicit calculations for the case of the (π+, π+p) reaction suggest that, while off-shell effects are very small, the Pauli exclusion principle has large qualitative effects throughout the (3,3) resonance region. It is of considerable interest to verify this experimentally. © 1979.