Related papers: Chiral Partners and their Electromagnetic Radiatio…
QCD sum rules serve as tools to investigate changing hadronic properties in a hot and/or dense nuclear medium. The role of chiral symmetry breaking and restoration effects in a medium can be addressed also in the heavy-light meson sector.…
In this work, the properties of the $\rho$ meson at rest in cold symmetric nuclear matter are studied. We make use of a chiral unitary approach to pion-pion scattering in the vector-isovector channel, calculated from the lowest order Chiral…
We report on recent work relating the medium effects observed in dilepton spectra in heavy-ion collisions to potential signals of chiral symmetry restoration. The key connection remains the approach to spectral function degeneracy between…
The QCD vacuum shows the dynamical breaking of chiral symmetry. In the hot/dense QCD medium, the chiral order parameter such as $ < \bar q q > $ is expected to change as function of temperature $T$ and density $\rho$ of the medium, and its…
Recent developments on medium modifications of hadron properties in dense and hot hadronic matter are discussed. I will focus in particular on the behavior of spectral functions associated to collective scalar-isoscalar modes, kaons and…
We investigate the equation of state for a recently developed hybrid quark-meson-nucleon model under neutron star conditions of $\beta-$equilibrium and charge neutrality. The model has the characteristic feature that at increasing baryon…
Medium modifications of the electromagnetic spectral function in hadronic and quark-gluon matter are reviewed. A strong broadening of the $\rho$ meson, which dominates the spectral function in the low-mass regime, is quantitatively…
We discuss coexistence/mixing of different natures of hadronic composite (molecule) and elementary (quark-intrinsic) ones in hadron resonances. The discussions here are based on our previous publications on the origin of hadron resonances…
We point out that the spectrum of pseudoscalar and scalar mesons exhibits a cuasi-degenerate chiral nonet in the energy region around 1.4 GeV whose scalar component has a slightly inverted spectrum. Based on the empirical linear rising of…
We discuss recent developments concerning the in-medium properties of hadrons in dense and hot matter. The theoretical approaches are discussed in connection with the interpretation of experimental data from intermediate energy machines up…
We point out that meson spectrum indicates the existence of a degenerate chiral nonet in the energy region around 1.4 GeV with a slightly inverted spectrum with respect to a qq nonet. Based on this observation, the approximately linear…
We explore the mass splitting of the heavy-light mesons with chiral partner structure in nuclear matter. In our calculation, we employed the heavy hadron chiral perturbation theory with chiral partner structure and the nuclear matter is…
Soft-pion theorems are used to show how chiral symmetry constrains the contributions of low-momentum pions to the quark condensate, the pion decay constant and hadron masses, all of which have been proposed as signals of partial restoration…
Hadron spectroscopy is revealed by observing heavy resonances. Among various explanations of the internal structure of these hadronic states, hadronic molecules play a unique role. For hadronic molecules, which are associated with…
We analyze the restoration pattern of the members of the scalar and pseudoscalar meson nonets under chiral $O(4)$ and $U(1)_A$ symmetries. For that purpose, we exploit QCD Ward Identities (WI), which allow one to relate susceptibilities…
Chiral symmetry is one of the most fundamental symmetries in QCD. It is closely connected to hadron properties in the nuclear medium via the reduction of the quark condensate <bar{q}q>, manifesting the partial restoration of chiral…
Physics of the low-lying and high-lying hadrons in the light flavor sector is reviewed. While the low-lying hadrons are strongly affected by the spontaneous breaking of chiral symmetry, in the high-lying hadrons the chiral symmetry is…
Recent developments in the evaluation of vector-meson spectral functions in hot and dense matter are discussed with emphasis on connections to the chiral phase transition in QCD. Model independent approaches including chiral low-density…
Given existing empirical spectral patterns of excited hadrons it has been suggested that chiral symmetry is approximately restored in excited hadrons at zero temperature/density (effective symmetry restoration). If correct, this implies…
QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive…