Direct E+E- Pair Production by 360 Gev-Cpi- in Hydrogen

We report on direct production of positron-electron pairs by 360-GeV/c pions incident on the Fermilab 30-in. hydrogen bubble chamber. These high-energy data are the first with liquid hydrogen, and are shown to be in agreement with quantum-electrodynamic calculations. For the region of four-momentum transfer considered, quantum electrodynamics predicts essentially equal contributions from production in the Coulomb field of the nucleus and the atomic electron.