Observation of a fourth upsilon state in e+e- annihilations

A fourth state in the upsilon energy region has been seen in e/sup +/e/sup -/ collisions at the Cornell Electron Storage Ring. A resonance is observed with a mass 1112 +- 5 MeV above the lowest upsilon state. The 9.6-MeV rms width is greater than the 4.6-MeV energy resolution of the e/sup +/e/sup -/ beams. The observed characteristics of the new state make it a likely candidate for the 4/sup 3/S state of the bb-bar system, lying above the threshold for the production of B mesons.