Twoloop electroweak corrections for the K→πνν̄ decays
Abstract
The rare K→πνν̄ decays play a central role in testing the standard model and its extensions. Upcoming experiments plan to measure the decay rates with high accuracy. Yet, unknown higherorder electroweak corrections result in a sizeable theory error. We remove this uncertainty by computing the full twoloop electroweak corrections to the topquark contribution X_{t} to the rare decays K_{L}→π^{0}νν̄, K^{+}→π^{+}νν̄, and B→X_{d,s}νν̄ in the standard model. The remaining theoretical uncertainty related to electroweak effects is now far below 1%. Finally we update the branching ratios to find Br(K_{L}→π^{0}νν̄)=2.43(39)(6)×10^{11} and Br(K^{+}→π^{+}νν̄)=7.81(75)(29)×10^{11}. The first error summarizes the parametric, the second the remaining theoretical uncertainties.
 Publication:

Physical Review D
 Pub Date:
 February 2011
 DOI:
 10.1103/PhysRevD.83.034030
 arXiv:
 arXiv:1009.0947
 Bibcode:
 2011PhRvD..83c4030B
 Keywords:

 13.25.Es;
 12.15.Hh;
 12.15.Lk;
 Decays of K mesons;
 Determination of KobayashiMaskawa matrix elements;
 Electroweak radiative corrections;
 High Energy Physics  Phenomenology
 EPrint:
 20 pages, 6 figures