UC Berkeley

We report on an improved measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase γ through a Dalitz plot analysis of neutral D meson decays to KS0π+π- and KS0K+K- produced in the processes B →DK, B →D*K with D*→Dπ0, Dγ, and B →DK* with K* →KS0π. Using a sample of 383×106 BB̄ pairs collected by the BABAR detector, we measure γ=(76±22±5±5)° (mod 180°), where the first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the uncertainty on the description of the Dalitz plot distributions. The corresponding 2-standard-deviation region is 29°<γ<122°. This result has a significance of direct CP violation (γ ≠0) of 3.0 standard deviations. © 2008 The American Physical Society.