Lattice calculation of the π0, η and η' transition form factors and the hadronic light-by-light contribution to the muon g-2

In this paper we present a first ab initio calculation of the 0, rl and rl' transition form factors performed with physical light-quark masses. We provide a complete parametrization of the form factors that includes both single and double-virtual kinematics. Our results are compared with experimental measurements of the form factors in the spacelike region and with the measured two-photon decay widths. In a second step, our parametrizations of the transition form factors are used to compute the dominant pseudoscalar-pole contributions to the hadronic light-by-light scattering in the muon g - 2. Our final result reads ahlbl;ps-pole mu = (85.1 + 5.2) x 10-11. Although the pion-pole is dominant, we confirm that, together, the rl and rl' provide roughly half of its contribution.