Estimating CP violation in Bc→BK0+BK¯0→Bπ±e∓νe decays

In this paper, we investigate the CP asymmetries ACPpm and ACPmp in Bc±→B±K0+B±K¯0→B±π±e∓νe and Bc±→B±K0+B±K¯0→B±π∓e±νe decays; both of them consist of three parts: the indirect CP violations in K0−K¯0 mixing ACP,mixpm and ACP,mixmp, the direct CP violations in Bc decay ACP,dirpm and ACP,dirmp, and the new CP violation effects ACP,intpm and ACP,intmp, which originate from the interference between the amplitude of the Bc−→B−K0(K¯0)→B−π−e+νe(π+e−ν¯e) decay with the difference between the oscillating effect of K0→K¯0 and that of K¯0→K0. The strong phase differences of the direct CP asymmetries ACP,dirpm and ACP,dirmp arise from K0−K¯0 mixing parameters. ACPpm and ACPmp are of the order of O(10−4) and O(10−3), respectively. The new CP violation effect ACP,intpm plays a dominant role in ACPpm; the CP asymmetry ACPmp is dominated by the indirect CP violation ACP,mixmp, so the CP asymmetry ACPpm provides an ideal place to study the new CP violation effect. We derive another two asymmetry observables ACPpp and ACPmm, which are dominated by K0−K¯0 mixing. The observables ACPpm, ACPmp, ACPpp, and ACPmm are hopefully to be marginally observed at the LHC experiment and the HL-LHC experiment.