Comment on “Measurement of the space-time extent of the hard-photon emitting source in heavy-ion collisions at 100 MeV/nucleon”

Abstract

In a recent paper [Phys. Rev. C 55, 2521 (1997)] two-photon coincidences were studied for three nuclear reactions. From a correlation analysis, the authors evaluated the size and lifetime of the emitting source. In this Comment we correct some arguments used in the comparison of the extracted and estimated sizes, and show that the parametrization of the relative-momentum correlations leads to values which should not be assigned to the space-time extent of the source.