Charm photoproduction at 20 GeV

Sixty-two charm events have been observed in an exposure of the SLAC Hybrid Facility toa backward sacttered laser beam. Based on 22 neutral and 21 charged decays we have measured the charmed-meson lifetimes to be τ_D⁰=(6.8_-1.8+2.3)×10^-13 sec, τ_D^±=(7.4_-2.0+2.3)×10^-13 sec and their ratio τ_D^±τ_D⁰=1.1_-0.3+0.6. The inclusive charm cross section at a photon energy of 20 GeV has been measured to be 56_-23⁺²⁴ nb. Evidence is presented for a non-DD̄ component to charm production, consistent with (35±{}20)% Λc⁺ production and some D^*± production. We have found no unambiguous F decays.