Key points are not available for this paper at this time.
An experiment to search for the production of neutral penetrating particles decaying into electron-positron pairs was performed with a 2. 5-GeV electron beam. A total of 0. 027 C was injected into a tungsten target. No such particle is found. Constraints on coupling constants ₄ and _ are given.
Konaka et al. (Mon,) studied this question.