The conformal symmetry SO(d,2) of the massless particle in d dimensions, or
superconformal symmetry OSp(N\4), SC(2.2\N), OSp(8\N) of the superparticle
in d = 3,4,6 dimensions respectively, had been previously understood as th
e global Lorentz symmetry and supersymmetries of 2T physics in d + 2 dimens
ions. By utilizing the gauge symmetries of 2T physics, it is shown that the
dynamics can be cast in terms of superspace coordinates, momenta and theta
variables or in terms of supertwistor variables a la Penrose and Ferber. I
n 2T physics these can be gauge transformed to each other. In the supertwis
tor version the quantization of the model amounts to the well known oscilla
tor formalism for non-compact supergroups. (C) 2000 Elsevier Science B.V. A
ll rights reserved.