Physical Review C
We have measured the differential cross section for the gamma He-3 -> pi(+)t reaction. This reaction was studied using the Continuous Electron Beam Accelerator Facility (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 He-3 target. The differential cross sections for the gamma He-3 -> 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.
Nasseripour, R., Berman, B. L., Adhikari, K. P., Adikaram, D., Anghinolfi, M., Ball, J., ... & Branford, D. (2011). Coherent photoproduction of π+ from He 3. Physical Review C, 83(3), 034001.