Electromagnetically induced flow in heavy ion collisions

5 Nov 2019, 15:00
HongKong Room (Wanda Reign Wuhan Hotel)

HongKong Room

Wanda Reign Wuhan Hotel

Oral Presentation New theoretical developments Parallel Session - New theoretical developments I


Dmitri Kharzeev


I will discuss 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, that is a charge-odd directed flow
$\Delta v_1$ that is odd in rapidity, noting that it is induced by magnetic fields (a la Faraday and Lorentz)
and by electric fields (the Coulomb field from the charged spectators). In addition, we find a
charge-odd $\Delta v_3$ 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 $\langle p_T \rangle$ and the elliptic flow $\Delta v_2$. Although their
magnitudes are comparable to the charge-odd $\Delta v_1$ and $\Delta v_3$, they have a different physical origin, namely the Coulomb forces within the plasma. Recent ALICE and STAR measurements confirm these effects but exhibit an opposite sign and bigger magnitude. I will discuss possible ingredients missing in the theory that would possibly resolve this apparent mismatch.

Primary authors

Umut Gursoy Dmitri Kharzeev Krishna Rajagopal (Massachusetts Inst. of Technology (US)) Prof. Chun Shen (Wayne State University) Mr Eric Marcus (Utrecht University)

Presentation Materials