Hadronic and electromagnetic probes of hot and dense nuclear matter

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 dynamically broken chiral symmetry in a hot and dense hadronic medium. It follows from chiral symmetry alone that parity partners of hadronic correlation functions must become identical when the symmetry is restored. The assessment of medium effects in the vector channel, which governs the dilepton production, thus necessitates a simultaneous treatment of the vector and axialvector degrees of freedom. While significant progress in this respect has been made some open questions remain in establishing a rigorous link in the mass region below 1 GeV. From the present calculations a suggestive 'quark-hadron duality' emerges near the phase boundary. It implies substantial medium effects in the dilepton signal from the hadronic phase which smoothly matches a perturbative description within the plasma phase.

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Chiral symmetry restoration and dileptons in relativistic heavy ion collisions

Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion Collisions

Transport-theoretical Description of Nuclear Reactions

Properties of hot and dense matter from relativistic heavy ion collisions

The spectral function of the rho meson in nuclear matter

What qcd sum rules tell about the rho meson

http://cds.cern.ch/record/347800/files/9803009.pdf

Coherent photoproduction of pions on nuclei in a relativistic, nonlocal model

A relativistic and non-local model for the coherent photoproduction of pions on spin-zero nuclei is presented. The production operator is derived from an effective Lagrangian model that contains all the degrees of freedom known to contribute to the elementary process. Using the framework of DWIA, the matrix elements of this operator are evaluated using relativistic bound state wave functions. Final state interactions are accounted for via a pion-nucleus optical potential. The effects of in-medium modifications of the production operator are discussed. We give results for $^{12}C$ and $^{40}Ca$, and compare our calculations to the data of the A2 collaboration at MAMI.

W. Peters

Papers

The spectral function of the rho meson in nuclear matter

What qcd sum rules tell about the rho meson

Coherent photoproduction of pions on nuclei in a relativistic, nonlocal model

Coherent Photoproduction of Pions on Nuclei in a relativistic, non-local Model

Coherent photoproduction of pions on spin-zero nuclei in a relativistic, non-local model