The complete  ΔS = 2 Hamiltonian in the nexttoleading order
Abstract
We present the complete nexttoleading order shortdistance QCD corrections to the effective  ΔS = 2 Hamiltonian in the Standard Model. The calculation of the coefficient η_{3} is described in great detail. It involves the twoloop mixing of bilocal structures composed of two  ΔS = 1 operators into  ΔS = 2 operators. The nexttoleading order corrections enhance η_{3} by 27% to η_{3} = 0.47 _{0.04}^{+0.03} thereby affecting the phenomenology of the CP parameter ɛ_{K} sizeably. η_{3} depends on the physical input parameters m_{t}, m_{c} and Λ _{overlineMS} only weakly. The quoted error stems from renormalization scale dependences, which have reduced compared to the old leading log result. The known calculation of η_{1} and η_{2} is repeated in order to compare the structure of the three QCD coefficients. We further discuss some field theoretical aspects of the calculation such as the renormalization group equation for Green functions with two operator insertions and the renormalization scheme dependence caused by the presence of evanescent operators.
 Publication:

Nuclear Physics B
 Pub Date:
 February 1996
 DOI:
 10.1016/05503213(96)003240
 arXiv:
 arXiv:hepph/9604330
 Bibcode:
 1996NuPhB.476...27H
 Keywords:

 High Energy Physics  Phenomenology
 EPrint:
 68 pages, requires LaTeX2e and the standard LaTeXpackages epsf.sty, rotate.sty, a4.sty, subeqn.sty, cite.sty, array.sty, dcolumn.sty