Search for CP Violation and Measurement of the Branching Fraction in the Decay D0 → KS0 KS0

Abstract

We report a study of the decay D0→KS0KS0 using 921 fb-1 of data collected at or near the (4S) and (5S) resonances with the Belle detector at the KEKB asymmetric energy e+e- collider. The measured time-integrated CP asymmetry is ACP(D0→KS0KS0)=(-0.02±1.53±0.02±0.17)%, and the branching fraction is B(D0→KS0KS0)=(1.321±0.023±0.036±0.044)×10-4, where the first uncertainty is statistical, the second is systematic, and the third is due to the normalization mode (D0→KS0π0). These results are significantly more precise than previous measurements available for this mode. The ACP measurement is consistent with the standard model expectation.