Measurement of the differential cross section for radiative formation of helium-four by deuteron bombardment of deuterium at 376 MeV

Differential cross sections have been measured for d + d→4He + γ at theta/sub γ/(cm) = 730 and 910 for a deuteron energy of 376 MeV. The measurements were performed at the Laboratoire National Saturne at Saclay, France. A two-arm coincidence method was employed, detecting the 4He in the SPES I magnetic spectrometer and the photon in one of two lead glass Cherenkov counters. Results are a factor of 60 lower than previously reported by Akimov et al. at 404 MeV, and about a factor of two higher than the measurements of the inverse reaction performed at Bonn by Arends et al. Because of the large statistical and systematic uncertainties of the measurements, the results are not inconsistent with time-reversal invariance in the electromagnetic interaction of hadrons involving purely isoscalar photons. Data corroborate the reported deviation from the sin22theta angular distribution characteristic of the electric quadrupole process that describes the reaction at lower energies. Results are also presented for the reactions pd→3Heγ, dp→3Heγ, pd→3Heπ0, pd→tπ +, and pp→dπ +. Their relation to the dd→4Heγ measurements as a verification of the experimental technique and of the absolute normalization is discussed