Doubly special relativity in position space starting from the conformal group

We propose version of doubly special relativity theory starting from position space. The version is based on deformation of ordinary Lorentz transformations due to the special conformal transformation. There is unique deformation which does not modify rotations. In contrast to the Fock-Lorentz realization (as well as to recent position-space proposals), maximum signal velocity is position (and observer) independent scale in our formulation by construction. The formulation admits one more invariant scale identified with radius of three-dimensional space-like hypersection of space-time. We present the Lagrangian action for geodesic motion of a particle on the DSR space. The corresponding dynamics and kinematics are discussed in some details. In particular, we demonstrate that there is no of the problem of total momentum in the theory. (C) 2004 Elsevier B.V. All rights reserved.