Discovery of the new particle J

We present a description of an experiment carried out at the 30 GeV Alternating Gradient Synchrotron of the Brookhaven National Laboratory. The experiment used a high intensity slow extracted proton beam of between 1010 and 2·1012 protons per pulse and measured the e+e− mass spectrum from the reaction p + Be→e+e− + X. The results of this experiment shows the production of a new type of particle, J, which decays to e+e− with a width consistent with zero.