%0 Journal Article
%T Sum rule analysis of vector and axial-vector spectral functions with excited states in vacuum
%A Paul M. Hohler
%A Ralf Rapp
%J Physics
%D 2012
%I arXiv
%R 10.1016/j.nuclphysa.2012.08.003
%X We simultaneously analyze vector and axial-vector spectral functions in vacuum using hadronic models constrained by experimental data and the requirement that Weinberg-type sum rules are satisfied. Upon explicit inclusion of an excited vector state, viz. rho', and the requirement that the perturbative continua are degenerate in vector and axial-vector channels, we deduce the existence of an excited axial-vector resonance state, a1', in order that the Weinberg sum rules are satisfied. The resulting spectral functions are further tested with QCD sum rules.
%U http://arxiv.org/abs/1204.6309v2