Observation of D0 ??0? and Search for CP Violation in Radiative Charm Decays

Abstract

We report the first observation of the radiative charm decay D0??0? and the first search for CP violation in decays D0??0?, ??, and K??0(892)?, using a data sample of 943 fb-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fraction is measured to be B(D0??0?)=(1.77�0.30�0.07)�10-5, where the first uncertainty is statistical and the second is systematic. The obtained CP asymmetries ACP(D0??0?)=+0.056�0.152�0.006, ACP(D0???)=-0.094�0.066�0.001, and ACP(D0?K??0?)=-0.003�0.020�0.000 are consistent with no CP violation. We also present an improved measurement of the branching fractions B(D0???)=(2.76�0.19�0.10)�10-5 and B(D0?K??0?)=(4.66�0.21�0.21)�10-4. � 2017 American Physical Society.