Compton scattering from He 4 at 61 MeV

Abstract

The Compton scattering cross section from He4 has been measured with high statistical accuracy over a scattering angle range of 40°-159° using a quasimonoenergetic 61-MeV photon beam at the High Intensity Gamma-Ray Source. The data are interpreted using a phenomenological model sensitive to the dipole isoscalar electromagnetic polarizabilities (αs and βs) of the nucleon. These data can be fit with the model using values of αs and βs that are consistent with the currently accepted values. These data will serve as benchmarks of future calculations from effective field theories and lattice quantum chromodynamics.