Low-mass dilepton production through transport process in quark-gluon plasma

Understand

We attempt to understand the low-mass dielectron enhancement observed by PHENIX Collaboration at Relativistic Heavy Ion Collider (RHIC) by transport peak in the spectral function.

• On the basis of the second-order formalism of relativistic dissipative hydrodynamics, we parameterize the spectral function in low-frequency and long-wavelength region by two transport coefficients, electric diffusion coefficient $D$ and relaxation time $\tau_{\rm J}$, and compared our theoretical dielectron spectra with the experimental data.
• We study spectrum of dielectrons produced in relativistic heavy ion collisions by using the profile of matter evolution under full (3+1)-dimensional hydrodynamics.
• We find that the experimental data require the diffusion coefficient to be $D\geq 2/T$, with $T$ being temperature.