Violation of Vector Dominance in the Vector Manifestation
Abstract
Description
The vector manifestation (VM) is a new pattern for realizing the chiral symmetry in QCD. In the VM, the massless vector meson becomes the chiral partner of pion at the critical point, in contrast with the restoration based on the linear sigma model. Including the intrinsic temperature dependences of the parameters of the HLS Lagrangian determined from the underlying QCD through the Wilsonian matching together with the hadronic thermal corrections, we present a new prediction of the VM on the direct photon-$π$-$π$ coupling which measures the validity of the vector dominance (VD) of the electromagnetic form factor of the pion. We find that the VD is largely violated at the critical temperature, which indicates that the assumption of the VD made in several analysis on the dilepton spectra in hot matter may need to be weakened for consistently including the effect of the dropping mass of the vector meson.
8 pages, no figure, talk given at Fifth Symposium on "Science of Hadrons under Extreme Conditions", March 18-20, 2003, JAERI, Ibaraki, Japan
8 pages, no figure, talk given at Fifth Symposium on "Science of Hadrons under Extreme Conditions", March 18-20, 2003, JAERI, Ibaraki, Japan