Soft supersymmetry breaking, scalar top-charm mixing and Higgs signatures

The squark mass-matrix from the soft supersymmetry (SUSY) breaking sector contains a rich flavor-mixing structure that allows O(1) mixings among top- and charm-squarks while being consistent with all the existing theoretical and experimental bounds. We formulate a minimal flavor-changing-neutral current scheme in which the squark mixings arise from the non-diagonal scalar trilinear interactions. This feature can be realized in a class of new models with a horizontal U(1)g symmetry which generates realistic quark-mass matrices and provides a solution to the SUSY mu-problem. Finally, without using the mass-insertion approximation, we analyze SUSY radiative corrections to the H(+/-)bc and h(0)tc couplings, and show that these couplings can reveal exciting new discovery channels for the Higgs boson signals at the Tevatron and the LHC. (C) 2002 Elsevier Science B.V. All rights reserved.