====== TTP10-16 Epsilon-K at NNLO: The Charm-Top-Quark Contribution ======
 
 
   <hidden TTP10-16  Epsilon-K at NNLO: The Charm-Top-Quark Contribution > We perform a next-to-next-to-leading order (NNLO) QCD analysis of the 
charm-top-quark contribution eta_ct to the effective Delta S = 2 
Hamiltonian in the Standard Model. eta_ct represents an important part 
of the short distance contribution to the parameter epsilon_K. We
 calculate the three-loop anomalous dimension of the leading operator 
Q_S2, the three-loop mixing of the current-current and penguin 
operators into Q_S2, and the corresponding two-loop matching 
conditions at the electroweak, the bottom-quark, and the charm-quark
 scale. As our final numerical result we obtain eta_ct = 0.494 +/-
0.046, which is roughly 7% larger than the next-to-leading-order (NLO)
 value eta_ct(NLO) = 0.455 +/- 0.069. This results in a prediction for
 epsilon_K = (1.99 +/- 0.25) x 10^(-3), which corresponds to an 
enhancement of approximately 3.3% with respect to the value obtained 
using eta_ct(NLO). </hidden>
|**Joachim Brod and Martin Gorbahn**  | 
|** Phys.Rev. D82 094026 2010  **  |
| {{preprints:2010:ttp10-16.pdf|PDF}} {{preprints:2010:ttp10-16.ps|PostScript}} [[http://arxiv.org/abs/1007.0684|arXiv]]   |
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