High spin gauge fields and two-time physics

All possible interactions of a point particle with background electromagnetic, gravitational and higher-spin fields are considered in the two-time physics worldline formalism in (d,2) dimensions. This system has a counterpart in a recent formulation of two-time physics in noncommutative field theory with local Sp(2) symmetry. In either the worldline or field theory formulation, a general Sp(2) algebraic constraint governs the interactions, and determines the equations that the background fields of any spin must obey. The constraints are solved in the classical worldline formalism ((h) over bar-->0 limit) as well as in the field theory formalism (all powers of (h) over bar). The solution in both cases coincide for a certain 2T to 1T holographic image which describes a relativistic particle interacting with background fields of any spin in (d-1, 1) dimensions. Two disconnected branches of solutions exist, which seem to have a correspondence as massless states in string theory, one containing low spins in the zero Regge slope limit, and the other containing high spins in the infinite Regge slope limit.