κ -deformed complex fields and discrete symmetries

We present a construction of κ -deformed complex scalar field theory with the objective of shedding light on the way discrete symmetries and C P T invariance are affected by the deformation. Our starting point is the observation that, in order to have an appropriate action of Lorentz symmetries on antiparticle states, these should be described by four-momenta living on the complement of the portion of the de Sitter group manifold to which κ -deformed particle four-momenta belong. Once the equations of motions are properly worked out from the deformed action, we obtain that the particle and antiparticle are characterized by different mass-shell constraints, leading to a subtle form of departure from C P T invariance. The remaining part of our work is dedicated to a detailed description of the action of deformed Poincaré and discrete symmetries on the complex field.