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HK: Fachverband Physik der Hadronen und Kerne

HK 49: Theorie

HK 49.1: Talk

Friday, March 14, 2008, 14:00–14:15, 2F

Vector-axialvector mixing in dilepton production and dropping meson masses — •Chihiro Sasaki¹, Masayasu Harada², and Wolfram Weise¹ — ¹Institut für Theoretische Physik T39, Physik-Department der TU München, D-85747 Garching — ²Department of Physics, Nagoya University, Nagoya, 464-8602, Japan

Changes of hadron properties are expected to be indications of chiral symmetry restoration in hot and/or dense QCD. Dropping masses of hadrons can be one of the prominent candidates of the strong signal of melting quark condensate ⟨qq⟩ which is an order parameter of spontaneous chiral symmetry breaking.

Due to the pion in a heat bath, the vector and axialvector current correlators are mixed. Thus axialvector mesons play an important role in exploring the critical properties associated with chiral symmetry restoration. Recently a chiral approach based on a systematic perturbation scheme including both vector and axialvector mesons as well as pions has been constructed. In this approach the dropping meson masses are inevitably achieved at chiral phase transition.

In this talk we discuss the importance of the axialvector meson in thermal dilepton productions assuming dropping masses. We show that there exists a significant change in structure above/below ρ peak, which corresponds to the vector-axialvector mixing and has been missed in previous calculations with dropping ρ scenarios.