Measurement of the B⁰-anti-B⁰ oscillation frequency in hadronic B⁰ Decays

B^0-anti-B^0 flavor oscillations have been studied in 20.7 fb-1 of e^+e^- annihilation data collected in 1999 and 2000 with the BABAR detector at center-of-mass energies near the Upsilon(4S) resonance. The event sample consists of one B^0 meson fully reconstructed in a hadronic decay mode, while the flavor of the recoiling B^0 in the event is determined with a tagging algorithm that exploits the correlation between the flavor of the heavy quark and the charges of its decay products. By fitting the time development of the observed mixed and unmixed final states, the B^0-anti-B^0 oscillation frequency, Delta_md, is determined to be 0.519+/- 0.020+/- 0.016 ps^{-1}.