Exotic quarks in superstring models: implications on CP violation and heavy-meson mixing

Abstract

At low energies, superstring models lead to an effective E₆ theory containing exotic charge -(⅓ quarks, denoted h. Here we work out the consequences of the mixing of h with the b quark, on CP violation, and heavy-neutral-meson systems. This mixing is found to remove the lower bound on m_t from ε and significantly reduces the prediction for ε'/ε. While B⁰-B⁻⁰ mixing remains unaltered, there is a considerable enchancement of D⁰-D⁻⁰ mixing from supersymmetric contributions.