SIMULTANEOUS MEASUREMENT OF THE (GAMMA,P) (GAMMA-N) CROSS-SECTION RATIO IN HE-4 AS A TEST OF CHARGE-SYMMETRY

We have measured (gamma,p) and (gamma,n) differential yields at 90-degrees for the two-body photodisintegration of He-4 using tagged photons of energy E(gamma) = 25-60 MeV. Data for both channels were obtained simultaneously using windowless DELTAE-E telescopes to detect the He-3 and H-3 recoils. The ratio of our angle-integrated yields, which is insensitive to systematic uncertainties due to the simultaneity of the measurements, agrees with calculations employing only charge-symmetric nuclear interactions. Thus, within the present errors, our data show no evidence of a significant charge-symmetry violation in He-4 in this energy range.