  The superconducting instabilities of the doped repulsive 2D Hubbard model are
studied in the intermediate to strong coupling regime with help of the
Dynamical Cluster Approximation (DCA). To solve the effective cluster problem
we employ an extended Non Crossing Approximation (NCA), which allows for a
transition to the broken symmetry state. At sufficiently low temperatures we
find stable d-wave solutions with off-diagonal long range order. The maximal
$T_c\approx 150K$ occurs for a doping $\delta\approx 20%$ and the doping
dependence of the transition temperatures agrees well with the generic
high-$T_c$ phase diagram.
