Study of Decay Dynamics and CP Asymmetry In D⁺ → K{_L^0} e⁺ν_e Decay


Using 2.92 fb⁻¹ of electron-positron annihilation data collected at √s̅ = 3.773 GeV with the BESIII detector, we obtain the first measurements of the absolute branching fraction B(D⁺ → K(L)⁰e⁺ν(e)) = (4.481 ± 0.027(stat) ± 0.103(sys))% and the CP asymmetry A(CP)^{D+ → K(L)⁰e⁺ν(e)} = (-0.59 ± 0.60(stat) ± 1.48(sys))%. From the D⁺ → K(L)⁰e⁺ν(e) differential decay rate distribution, the product of the hadronic form factor and the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element, f(+)^K (0) |V(cs)|. is determined to be 0.728 ± 0.006(stat) ± 0.011(sys). Using |V(cs)| from the SM constrained fit with the measured f(+)^K (0) |V(cs)|, f(+)^K(0) = 0.748 ± 0.007(stat) ± 0.012(sys) is obtained, and utilizing the unquenched Lattice QCD (LQCD) calculation for f(+)^K(0), |V(cs)| = 0.975 ± 0.008(stat) ± 0.015(sys) ± 0.025(LQCD).



Branching fractions (Nuclear physics), Mesons, Charge-parity asymmetry, Uncertainty, Leptonic decays

This work is supported in part by National Key Basic Research Program of China under Contract No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts No. 11125525, No. 11235011, No. 11322544, No. 11335008, and No. 11425524; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts No. 11179007, No. U1232201, and No. U1332201; CAS under Contracts No. KJCX2-YW-N29 and No. KJCX2-YW-N45; German Research Foundation DFG under Contract No. Collaborative Research Center CRC-1044; Ministry of Development of Turkey under Contract No. DPT2006K-120470; Russian Foundation for Basic Research under Contract No. 14-07-91152; US Department of Energy under Contracts No. DE-FG02-04ER41291, No. DE-FG02-05ER41374, No. DE-SC0012069, and No. DESC0010118; and WCU Program of National Research Foundation of Korea under Contract No. R32-2008-000-10155-0. This work is also supported by the NSFC under Contracts No. 11275209 and No. 11475107.


©2015 American Physical Society