Title:Â Effective Field Theory for Positronium in Relativistic Motion
Abstract:Â This work introduces a method that utilizes effective field theory (EFT) to establish a set of systematic power-counting rules and to compute the equal-time wave function of a relativistic moving positronium at the leading order. The positronium is perturbatively expanded in terms of the Fock states to give a definition of the equal-time wave function, which can be solved using old-fashioned perturbation theory. Using the leading-order wave function, the photon momentum distribution is evaluated to explicitly show the dynamic effects of the Lorentz boost. This work also provides some hints on the study of heavy quarkonium systems.