Prediction of the CP asymmetry C00 in {B}^0to {D}^0overline{D^0} decay

Abstract

Of all Bto Doverline{D} decays, the {B}^0to {D}^0overline{D^0} decay has the smallest observed branching ratio as it takes place primarily via the suppressed W-exchange diagram. The CP asymmetry for this mode is yet to be measured experimentally. By exploiting the relationship among the decay amplitudes of Bto Doverline{D} decays (using isospin and topological amplitudes) we are able to relate the CP asymmetries and branching ratios by a simple expression. This enables us to predict the CP asymmetry C00 in {B}^0to {D}^0overline{D^0} . While the predicted central values of C00 are outside the physically allowed region, they are currently associated with large uncertainties owing to the large errors in the measurements of the {B}^0to {D}^0overline{D^0} branching ratio (B00), the other CP asymmetries C+− (of B0 → D+D−) and ACP (of {B}^{+}to {D}^{+}overline{D^0} ). With a precise determination of B00, C+− and ACP, one can use our analytical result to predict C00 with a reduced error and compare it with the experimental measurement when it becomes available. The correlation between B00 and C00 is an interesting aspect that can be probed in ongoing and future particle physics experiments such as LHCb and Belle II.