Unitarity cuts and reduction to master integrals in d dimensions for   one-loop amplitudes
  We present an alternative reduction to master integrals for one-loop amplitudes using a unitarity cut method in arbitrary dimensions. We carry out the reduction in two steps. The first step is a pure four-dimensional cut-integration of tree amplitudes with a mass parameter, and the second step is applying dimensional shift identities to master integrals. This reduction is performed at the integrand level, so that coefficients can be read out algebraically. 
Charalampos Anastasiou, Ruth Britto, Bo Feng, Zoltan Kunszt, Pierpaolo   Mastrolia