Axial-vector contributions to the HFS of muonic hydrogen

Abstract

We review the axial-vector meson contributions to the HFS of muonic hydrogen. We evaluate the impact of the singly- and doubly-virtual asymptotic behavior of the transition form factors of the axial-vector mesons. As our main result, we find an opposite sign (and a factor of 2 difference) concerning previous analyses and a novel discussion of the hadronic modeling.