A five dimensional perspective on many particles in the Snyder basis of double special relativity

After a brief summary of Double Special Relativity (DSR), we concentrate on the five dimensional approach, which consistently introduce coordinates and momenta in the corresponding four-dimensional phase space, via a Hamiltonian approach. For the one particle case, the starting point is a de Sitter momentum space in five dimensions, with an additional constraint selected to recover the mass shell condition in four dimensions. Different basis of DSR can be recovered by selecting specific gauges to define the reduced four dimensional degrees of freedom. This is shown for the Snyder basis in the one particle case. In this article we generalize the method to the many particles case and apply it again to the case of the Snyder basis. We show that the energy and momentum of the system, given by the dynamical variables that are generators of translations in space and time and which close the Poincaré algebra, are additive magnitudes. From this it results that the rest energy (mass) of a composite object does not have an upper limit, as opposed to a single component particle which does.