Rare D decays as a window to non-minimal supersymmetry

Flavour changing neutral currents in the charm sector are so highly suppressed due to the GIM mechanism and the simplicity of the Higgs sector in the Standard Model as to render them insignificant. This feature remains for the minimal supersymmetric version of the Standard Model. However, as soon as one allows for non-minimal realizations of supersymmetry, the picture changes very dramatically: D0-anti D0 mixing could be enhanced up to the present experimental bound; in that case one finds also BR(c→u+γ)∝10-5 leading to BR(D→ρ+γ)∝O(10-6). It is discussed how the supersymmetry contribution to D→ρ+γ can be distinguished from other possible sources. (orig.)