Next-to-leading order short distance QCD corrections to the effective $\Delta S=2$ Hamiltonian, implications for the $K_L$-$K_S$ mass difference

Abstract

We report on the results of a calculation of next-to leading order short distance QCD corrections to the coefficient ${\eta }_1$ of the effective $\Delta S=2$ Lagrangian in the standard model and discuss the uncertainties inherent in such a calculation. As a phenomenological application we comment on the contributions of short distance physics to the ${\mathrm{K}}_{\mathrm{L}}$--${\mathrm{K}}_{\mathrm{S}}$ mass difference. This report is based on research work done in collaboration with Ulrich Nierste.

Comments: 4 pages and 2 figures, uses LaTeX espcrc2 documentstyle option (all necessary files included in an uuencoded compressed tar file). Invited talk at the conference 'QCD94', Montpellier, France, 7-13 July 1994, to appear in the proceedings. TUM-T31-72/94