Buras Andrzej J, Gorbahn Martin, Haisch Ulrich, Nierste Ulrich
Physik Department, Technische Universität München, Garching, Germany.
Phys Rev Lett. 2005 Dec 31;95(26):261805. doi: 10.1103/PhysRevLett.95.261805. Epub 2005 Dec 27.
We calculate the charm quark contribution to the rare decay Kappa(+)--> pi(+) nunu in the next-to-next-to-leading order of QCD. This new contribution reduces the theoretical uncertainty in the relevant parameter Pc from +/-10.1% down to +/-2.4%, corresponding to scale uncertainties of +/-1.3%, +/-1.0%, +/-0.006, and +/-1.2 degrees in Beta(Kappa(+) --> pi(+) nunu) and in |V(td)|, sin2(Beta), and gamma extracted from the Kappa --> pinunu system. The error in Rho(c) = 0.37 +/- 0.04 is now fully dominated by the current uncertainty of +/-3.8% in the charm quark mass m(c). We find Beta(Kappa(+) --> pi(+)nunu) = (8.0 +/- 1.1) x 10(-11), where the quoted error stems almost entirely from the present uncertainties in m(c) and the Cabibbo-Kobayashi-Maskawa elements.
我们在 QCD 的次下一级领头阶计算了粲夸克对稀有衰变 K⁺→π⁺νν 的贡献。这一新贡献将相关参数 Pc 的理论不确定性从±10.1%降低至±2.4%，对应于在β(K⁺→π⁺νν)以及从 K→πνν 系统提取的|V(td)|、sin²β和γ中的尺度不确定性分别为±1.3%、±1.0%、±0.006 和±1.2°。Rho(c)=0.37±0.04 中的误差现在完全由粲夸克质量 m(c)当前±3.8%的不确定性主导。我们发现β(K⁺→π⁺νν)=(8.0±1.1)×10⁻¹¹，其中引用的误差几乎完全源于 m(c)和卡比博 - 小林 - 益川矩阵元目前的不确定性。
