THE ANGULAR DISTRIBUTION OF PHOTONS IN ORTHOPOS-ITRONIUM THREE PHOTON DECAY

The three photon decay of positronium was further studied using positronium source composed of ²²Na and silica aerogel and triple fast coincidence method.We measured the angular distribution of the photons in the large angle region under symmetrical geometry with respect to the third photon.The whole curve of the angular distribution of photons was given combining with the data in the small angle region which was published before.The results were in good agreement with theoretical predicted values.