Can transport peak explain the low-mass enhancement of dileptons at RHIC?

May 27, 2011, 7:10 PM
Salon Haendel AB (Imperial Palace)

Salon Haendel AB

Imperial Palace

Allée Impérial 74000 Annecy, France Tél. : +33 4 50 09 30 00
Parallel Electromagnetic probes Electromagnetic probes


Dr Yukinao Akamatsu (Nagoya University)


We propose a novel relation between the low-mass enhancement of dielectrons observed at PHENIX and transport coefficients of QGP such as the charge diffusion constant D and the relaxation time \tau. The observed low-mass enhancement sets a lower-bound on the diffusion constant, D > 2/T, with T being temperature. To reach this lower bound, we start with the second-order relativistic dissipative hydrodynamics by Israel and Stewart. The linearized hydrodynamic equation in external electromagnetic field gives a spectral function which is parametrized by D and \tau. Combining the spectral function with the full 3D hydrodynamic evolution, theoretical dielectron spectra and the experimental data are compared. Detailed analysis shows that the low-mass dilepton enhancement originates mainly from the high-temperature QGP phase where there is a large electric charge fluctuation as obtained from lattice QCD simulations.

Primary author

Dr Yukinao Akamatsu (Nagoya University)


Prof. Hideki Hamagaki (University of Tokyo) Prof. Tetsufumi Hirano (Sophia University) Prof. Tetsuo Hatsuda (University of Tokyo)

Presentation materials