Related papers: Fate of the $\rho$-$a_1$ mixing in dilepton produc…
We perform a systematic study of dilepton emission in a hot QCD medium based on three different scenarios of chiral mixing, each of which yields a characteristic structure in the vector spectral function. The in-medium spectral functions…
We study the structural change of the vector spectral function and integrated production rates of dileptons in the presence of the chiral mixing induced exclusively at finite density. The mixing produces multiple bumps and peaks around the…
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…
Using a rather complete description of the in-medium $\rho$ spectral function - being constrained by various independent experimental information - we calculate pertinent dilepton production rates from hot and dense hadronic matter. The…
We include effects of chiral symmetry and its restoration in the kinetic equations for baryon propagation and explore the consequences for $\eta$, $\pi^0$, $\rho$ and dilepton production in heavy-ion collisions at 1-2A GeV. Numerical…
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…
We study the vector-axialvector mixing in a hot medium and its evolution toward the chiral phase transition using different symmetry restoration scenarios based on the generalized hidden local symmetry framework. We show that the presence…
We evaluate currently available information on low-mass dilepton and direct-photon emission spectra measured in ultrarelativistic heavy-ion collisions. In the first part an attempt is made to develop a consistent picture of the in-medium…
Because of their weak interactions with the strongly interacting matter produced in relativistic heavy-ion collisions, dileptons provide an ideal probe of the early dynamics of these collisions. Here, we study dilepton production using a…
We discuss the recent status in the theoretical understanding of dilepton production in central heavy-ion reactions with the Pb-beam at the full CERN-SpS energy of 158 AGeV. In the low-mass region ($M\le$~1 GeV) a strong broadening of the…
We discuss how dilepton production is related to chiral symmetry and its restoration. We then analyse presently available data by the CERES collaboration in this context. We find that the present data do not support any conclusions…
Medium Effects in low-mass dilepton production in ultra-relativistic heavy-ion collisions are investigated using hadronic models. The rescattering of pions and rho mesons within a hot and dense hadron gas leads to substantial modifications…
The $\rho$ spectral function at finite temperature calculated using the real-time formalism of thermal field theory is used to evaluate the low mass dilepton spectra. The analytic structure of the $\rho$ propagator is studied and…
We study the possibility of $\rho-a_0$ mixing via N-N excitations in dense nuclear matter. This mixing is found to induce a peak in the dilepton spectra at an invariant mass equal to that of the $a_0$. We calculate the cross section for…
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…
The first part of this thesis focuses on the production of thermal dileptons from a hadronic gas at finite temperature. The rates are calculated by an expansion in Pion density and constrained by broken chiral symmetry and vacuum…
The properties of electromagnetic radiation from hot fireballs as created in ultra-relativistic heavy-ion collisions are reviewed. We first outline how the medium effects in the electromagnetic spectral function, which governs thermal…
The production of soft dileptons in a thermal mesonic medium is discussed in the context of recent CERN experimental data reported by the CERES Collaboration. We do not intend to give a general and critical review, but instead concentrate…
The effect of scalar and vector meson mixing on the dilepton radiation from hot and dense hadronic matter is estimated in different isospin channels. In particular, we study the effect of $\sigma$-$\omega$ and $\rho-a_0$ mixing and…
The current theoretical status in the analysis and interpretation of low-mass dilepton measurements in (ultra-) relativistic heavy-ion experiments is reviewed. Special emphasis is put on potential signals of (partial) restoration of…