Measurement of the partial width of the decay φ → e+ + e−

Abstract Evidence is presented for the process π − + p→ φ + n followed by φ → e + + e − . The branching ratio (φ→ e + + e − ) (φ→ total ) is found to be (7.2 ± 3.9) × 10 −4 , corresponding to a partial width for φ →e + + e − of 2.4 ± 1.5 keV/ c 2 and a coupling constant γ φ 2 4π of 1.9 −0.7 +2.9 .