Galilean superconformal symmetries

We consider the non-relativistic c -> infinity contraction limit of the (N = 2k)-extended D = 4 superconformal algebra su(2, 2; N), introducing in this way the non-relativistic (N = 2k)-extended Galilean superconformal algebra. Such a Galilean SUperconformal algebra has the same number of generators as su(2, 2 vertical bar 2k). The us (2k) algebra describes the non-relativistic internal symmetries, and the generators from the coset u(2k)/usp(2k) become central charges after contraction. (C) 2009 Elsevier B.V. All rights reserved.