BRST quantization of a particle in AdS(5)

We perform the quantization of a massive particle propagating on AdS(5). We use the twister formulation in which the action can be brought into a quad ratic form. We construct the BRST operator which commutes with AdS(5) isome tries forming SU(2,2). The condition of a consistent BRST quantization requ ires that the AdS energy E is quantized in units of the AdS, radius R, E = 1/2R(N-a + N-b + 4), With N-a, N-b being some non-negative integers. We als o argue that the mass operator will be identified with the moduli of the U( 1) central extension Z of the SU(2:2\4) algebra in the supersymmetric case. The spectrum of physical states with vanishing ghost number contains a par ticular subset of 'massless' SU(2,2) multiplets (including the bosonic part of the 'novel short' supermultiplets). We hope that our results will help to quantize also the string on AdS(5). (C) 1999 Published by Elsevier Scien ce B.V. All rights reserved.