Flavour changing neutral current effects from flavour dependent supergravity couplings

Abstract

We investigate the impact on low energy flavour mixing phenomena of the renormalisation group running of parameters in supersymmetric theories. We have explicitly chosen flavour dependent supergravity couplings. The renormalisation group equations are displayed in general matrix form. We work in a scale dependent basis such that the hierarchy in the quark masses can be more easily utilised. Simple analytic solutions are provided in matrix form (for general boundary conditions) when only the third generation Yukawa couplings are retained in the renormalisation group equations. We solve the evolution equations of the KM matrix and the supersymmetry breaking soft terms in the squark sector. We suggest a general parametrisation of the soft analytic terms, more suitable for non-universal supergravity couplings. We point out that for flavour dependent soft terms, there are new contributions to the neutron electric dipole moment. Finally, we consider a model with maximal flavour mixing in order to estimate the effects due to the renormalisation scale dependence.