Importance of the Doppler effect for the determination of the deuteron binding energy

The deuteron binding energy extracted from the reaction H-1(n,gamma)H-2 is reviewed with the exact relativistic formula, where the initial kinetic ene rgy and the Doppler effect are taken into account. We find that the negligi ble initial kinetic energy of the neutron could cause a significant uncerta inty which is beyond the errors available up to now. Therefore, we suggest an experiment which should include detailed information about the initial k inetic energy and the detection angle. It could reduce discrepancies among the recently reported values about the deuteron binding energy and pin down the uncertainty due to the Doppler broadening of the gamma ray. [S0556-281 3(99)04606-3].