Direct CP violation in Cabibbo-favored charmed meson decays and ? ′/ ? in SU(2) L × SU(2) R × U(1) B? L model

摘要

A bstract Since the standard model contribution is virtually absent, any observation of direct CP violation in the Cabibbo-favored charmed meson decays would be evidence of new physics. In this paper, we conduct a quantitative study on direct CP violation in D _(0)→ K _(?) π _(+), D ~( s )_(+) ?→? ηπ _(+)and D ~( s )_(+) ?→? η ′ π _(+)decays in the SU(2)~( L )×SU(2)~( R )×U(1)~( B ? L )gauge extension of the standard model. In the model, direct CP violation arises mainly from the interference between the decay amplitude coming from the SM left-left current operators and that from the right-right current operators induced by W ~( R )_(+) gauge boson exchange. Interestingly, the strong phase between the two amplitudes is evaluable, since it stems from difference in QCD corrections to the left-left and right-right current operators, which is a short-distance QCD effect given by ～ α s M W L 2 / 4 π log M W R 2 / M W L 2 $$ sim left({lpha}_sleft({M}_{W_L}^2ight)/4pi ight) log left({M}_{W_R}^2/{M}_{W_L}^2ight) $$ . We assess the maximal direct CP violation in the above decays in the SU(2)~( L )× SU(2)~( R )× U(1)~( B ? L )model. Additionally, we present a correlation between direct CP violation in these modes and one in K → ππ decay parametrized by ? ′, since W ~( R )_(+) gauge boson has a sizable impact on the latter.