Non-renormalization Theorem Originating in a New Fixed Point of the Vector Manifestation

摘要

We study the pion velocity at the critical temperature of chiral symmetryrestoration in QCD. Starting from the premise that the bare effective fieldtheory is to be defined from the underlying QCD, we incorporate the effects ofLorentz non-invariance into the bare theory by matching an effective fieldtheory to QCD at a suitable matching scale, and investigate how the Lorentznon-invariance existing in the bare theory influences physical quantities.Using the hidden local symmetry model as the effective field theory, where thechiral symmetry restoration is realized as the vector manifestation (VM), wefind that the pion velocity at the critical temperature receives neitherquantum nor (thermal) hadronic corrections at the critical temperature evenwhen we start from the bare theory with Lorentz symmetry breaking. This islikely the manifestation of a new fixed point in the Lorentz non-invariantformulation of the VM.