Rare decay K+ --> pi+ nunu at the next-to-next-to-leading order in QCD.

Journal article

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.

Authors: Buras, A; Gorbahn, M; Haisch, U; Nierste, U

• Journal: Physical Review Letters
• Volume: 95
• Issue: 26
• Pages: 261805
• Publication date: 2005-12-01
• DOI: 10.1103/physrevlett.95.261805
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English