Speaker
Description
We study nucleon-nucleon interaction up to next-to-next-to-leading order (NNLO) by applying time-ordered perturbation theory (TOPT) to covariant chiral effective field theory. Diagrammatic rules of TOPT, for the first time, are worked out for particles with non-zero spin and interactions involving time derivatives. We define the effective potential as a sum of two-nucleon irreducible contributions of time-ordered diagrams and derive the NN scattering equation, i.e. the Kadyshevsky equation, for the scattering amplitude. At leading order, we find that NN potential is perturbatively renormalizable, and the corresponding integral equation has unique solutions in all partial waves. Through evaluating the two-pion exchange contribution at the one-loop level, we formulate the NN interaction up to NNLO. A good description of phase shifts and deuteron properties is achieved by treating the full NNLO potential non-perturbatively.
