Measurement of CP asymmetry in B0 → K0sπ0π0 decays

Abstract

We present a measurement of the time-dependent C P asymmetry for the neutral B -meson decay into the C P = + 1 final state K 0 S π 0 π 0 , with K 0 S → π + π − . We use a sample of approximately 227 million B -meson pairs recorded at the Υ ( 4 S ) resonance with the BABAR detector at the PEP-II B -Factory at SLAC. From an unbinned maximum likelihood fit, we extract the mixing-induced C P -violation parameter S = 0.72 ± 0.71 ± 0.08 and the direct C P -violation parameter C = 0.23 ± 0.52 ± 0.13 , where the first uncertainty is statistical and the second systematic.