The problem of decomposition of unitary irreps of (super)tensorial (i.e., extended with tensorial charges) Poincare algebra w.r.t. its different subalgebras is considered. This requires calculation of little groups for different configurations of tensor charges. Particularly, for preon states (i.e., states with maximal supersymmetry) in different dimensions the particle content is calculated, i.e., the spectrum of usual Poincare representations in the preon representation of tensorial Poincare. At d = 4 results coincide with (and may provide another point of view on) the Vasiliev's results in field theories in generalized space-time. The translational subgroup of little groups of massless particles and branes is shown to be (and coincide with, at d = 4) a subgroup of little groups of "pure branes" algebras, i.e., tensorial Poincare algebras without vector generators. At 11 d it is shown that, contrary to lower dimensions, spinors are not homogeneous space of Lorentz group, and one have to distinguish at least 7 different kinds of preons. (C) 2003 Published by Elsevier Science B.V. References: 24
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