Charge-dependent flow induced by magnetic and electric fields in heavy ion collisions
Umut Gürsoy (Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands); Dmitri Kharzeev (Physics Department and RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973, USA, Department of Physics and Astronomy, Stony Brook University, New York 11794, USA); Eric Marcus (Institute for Theoretical Physics, Utrecht University, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands); Krishna Rajagopal (Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA); Chun Shen (Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA)
We investigate the charge-dependent flow induced by magnetic and electric fields in heavy-ion collisions. We simulate the evolution of the expanding cooling droplet of strongly coupled plasma hydrodynamically, using the iEBE-VISHNU framework, and add the magnetic and electric fields as well as the electric currents they generate in a perturbative fashion. We confirm the previously reported effect of the electromagnetically induced currents [Gursoy et al., Phys. Rev. C 89, 054905 (2014)], that is a charge-odd directed flow that is odd in rapidity, noting that it is induced by magnetic fields (à la Faraday and Lorentz) and by electric fields (the Coulomb field from the charged spectators). In addition, we find a charge-odd that is also odd in rapidity and that has a similar physical origin. We furthermore show that the electric field produced by the net charge density of the plasma drives rapidity-even charge-dependent contributions to the radial flow and the elliptic flow . Although their magnitudes are comparable to the charge-odd and , they have a different physical origin, namely the Coulomb forces within the plasma.
