Measurement of D(0)-(D)over-bar(0) mixing using the ratio of lifetimes for the decays D(0)-> K(-)pi(+), K(-)K(+), and pi(-)pi(+) RID C-5223-2009

We present a measurement of D(0)-(D) over bar (0) mixing parameters using the ratios of lifetimes extracted from a sample of D(0) mesons produced through the process D(*+) -> D(0)pi(+), which decay to K(-)pi(+), K(-)K(+), or pi(-)pi(+). The lifetimes of the CP-even, Cabibbo-suppressed modes K(-)K(+) and pi(-)pi(+) are compared with that of the CP-mixed, Cabibbo-favored mode K(-)pi(+) to obtain a measurement of y(CP), which in the limit of CP conservation corresponds to the mixing parameter y. The analysis is based on a data sample of 384 fb(-1) collected by the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider. We obtain y(CP) = [1.24 +/- 0.39(stat) +/- 0.13(syst)]%, which is evidence for D(0)-(D) over bar (0) mixing at the 3 sigma level, and Delta Y = [-0.26 +/- 0.36(stat) +/- 0.08(syst)]%, where Delta Y constrains possible CP violation. Combining this result with a previous BABAR measurement of y(CP) obtained from a separate sample of D(0) -> K(-)K(+) events, we obtain y(CP) = [1.03 +/- 0.33(stat) +/- 0.19(syst)]%.