Seminar in Hadronic Physics

Probing the QCD Phase Diagram via Thermal Dilepton Radiation: Status and Future Opportunities

Yiding Han

Rice University

Dilepton pairs generated during the evolution of the intense QCD medium in relativistic heavy-ion collisions serve as a potent tool to investigate the medium's attributes since they don't experience strong force. Their emission rate corresponds directly to the electromagnetic spectral function of the medium. Notably, dilepton emissions are mainly dictated by thermal radiation in the QGP phase for an invariant mass M_ll > 1.5 GeV/c². Conversely, for M_ll < 1 GeV/c², hadronic models can well describe these emissions. Insight into the electromagnetic spectral function's lower energy limit reveals vital transport properties, including electrical conductivity and relaxation time.

The RHIC Beam Energy Scan program provides a unique experimental framework to scrutinize these attributes right along the QCD medium's phase transition line. This seminar will encapsulate past, ongoing, and upcoming experimental endeavors at RHIC to deepen our understanding of this subject.