12-02-2010: Colloquium Harmen Warringa

29 - 01 - 2010

Friday 12 February 2010, 11:00h, at H331

Speaker: Harmen Warringa (Goethe-Universität, Frankfurt)

Title: "P- and CP-odd effects in heavy ion collisions"


In quantum chromodynamics (QCD) an imbalance in the number of right- and left-handed quarks will be induced by fluctuations of topological charge. This is a P- and CP-odd effect, and can potentially be relevant during heavy ion collisions. The question then is how one could investigate this imbalance in experiment. In this talk I will show that enormous magnetic fields are created in heavy ion collisions in the direction of angular momentum of the collision. I will explain that such imbalance naturally leads to generation of an electric current in the direction of the magnetic field. The magnitude of this current can be computed quantitatively. In heavy ion collisions, this current leads to separation of charge which in principle can be addressed experimentally by measuring specific charge correlations. As such these correlations could be a probe for P- and CP-odd effects in QCD. I will discuss recent results from the STAR collaboration on such charge correlations.