Investigation of the total charm-pair cross section in nonresonant e+e- annihilations at sqrt s =10.5 GeV.

CORNELL-CESR. Measurements of the total charm pair cross section in e+e- annihilations at sqrt(s)=10.5 GeV using two independent methods both of which are independent of the absolute magnitude of the hadronic D decay branching fractions. Method 1) involves a comparison of the inclusive numbers of charmed particles observed in several non leptonic decay modes with the number reconstructed in a 'tagged' set of events in which the charmed particle has already been found. Method 2) extracts a total charm pair production cross section using the semileptonic decays of charmed particles.