The Chiral Magnetic Effect: Measuring event-by-event P- and CP-violation with heavy ion-collisions

Gluon field configurations with nonzero topological charge induce Pand CP-odd effects. Such configurations are likely to be produced during heavy ion collisions. In this article, I will argue that in the intense (electromagnetic) magnetic field produced in non-central heavy ion collisions, topological charge creates an electromagnetic current in the direction of the magnetic field. This is the Chiral Magnetic Effect. It leads to separation of positive from negative charge along the direction of the magnetic field. I will point out that this effect can be investigated experimentally with a charge correlation study and will refer to interesting data from the STAR collaboration.