Spectral change of σ and ω mesons in a dense nuclear medium

Meson masses in a dense nuclear medium

The masses of the scalar (σ) and vector (ω) mesons and their widths in nuclear matter are studied in detail using the quark-meson coupling (QMC) model. It is shown that above normal nuclear matter density the effects of σ-ω mixing and the decay of the σ into 2π change the scalar meson mass considerably, while the vector meson mass remains near its mean-field value. We compare the QMC results wi...

σ and ω meson propagation in a dense nuclear medium

Vector mesons in dense matter

We will summarize the progress in understanding the changes in the vector meson spectral density in nuclear medium using the constraint equations obtained from the Borel transformed dispersion relation and QCD Operator Product Expansion. We will discuss the results for the scalar mass shift and dispersion effects (three momentum dependence) for the light quark system (ρ, ω), the strange quark s...

Chiral Transition in QCD and Scalar Correlations

We review recent developments in exploring possible precursory phenomena of partial restoration of chiral symmetry in nuclear medium by examining the spectral function in the scalar channel. We emphasize that the wave function renormalization of the pion in the medium plays an essential role to induce the decrease of the pion decay constant as the order parameter of chiral transition. We also s...

Chiral Transition in Nuclear Medium and Relevant Observables

We discuss how the possible changes of hadron properties can be tested, associated with the chiral transition in nuclear medium; the hadrons discussed are the vector mesons, the σ meson and the chiral partner of the nucleon. We emphasize that the proper quantity is the spectral function which describes the nuclear medium having a hadron; the analysis of electro-quasielastic reactions, for insta...