Coherent Photoproduction of pi^+ from 3^He

Abstract

We have measured the differential cross section for the $\gamma$${}^3$He$\to {\pi }^{+}t$ reaction. This reaction was studied using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Real photons produced with the Hall-B bremsstrahlung tagging system in the energy range from 0.50 to 1.55 GeV were incident on a cryogenic liquid ${}^3$He target. The differential cross sections for the $\gamma$${}^3$He$\to {\pi }^{+}t$ reaction were measured as a function of photon-beam energy and pion-scattering angle. Theoretical predictions to date cannot explain the large cross sections except at backward angles, showing that additional components must be added to the model.

11 pages, 16 figures