Impulse Approximation and Multiple-Scattering Series forπ+d↔ppat High Energy

A new model for ${\pi }^{+}d\leftrightarrow pp$ at high energy, based on the impulse approximation, is formulated. It is observed that the shape of the differential cross section for this process is qualitatively consistent with the deuteron momentum-space density, implying that nuclear structure plays a dominant role in determining the momentum-transfer distribution. Despite the drastically nondiffractive nature of the reaction, a multiple-scattering-like series can be formulated from the Lippmann-Schwinger equation and evaluated by the linearized-propagator method. The resulting amplitude yields a good four-parameter fit to $pp\to {\pi }^{+}d$ data at 3.74, 10.0, 14.2, 21.1, and 24.0 GeV/c. Arguments against some aspects of the Reggeistic interpretation of this process are also presented.