University of Minnesota
School of Physics & Astronomy

Nuclear Physics Seminar

Wednesday, December 2nd 2009
1:25 pm:
Nuclear Physics Seminar in 435 Physics
Speaker: Sener Ozonder, University of Minnesota
Subject: Chiral Magnetic Effect

The vacuum of QCD is infinitely degenerate, but perturbative processes such as scattering or particle annihilation/creation do not change the vacuum of the gluons. However, nonperturbative topological solutions of the gluon field such as sphalerons, which are not suppressed at finite temperature, bring about transitions between different vacua. The Chern-Simons winding number associated with those transitions controls the anomaly of the U(1) axial current of the quarks. As a result of nonconservation of the axial current, sphalerons produce more left handed quarks and antiquarks than right handed ones, or vice versa. Under the influence of the strong magnetic field produced by off-central heavy-ion collisions, quark matter with nonzero net chirality (or handedness) polarizes along the axis of the magnetic field so that positively and negatively charged quarks accumulate oppositely, i.e., an electric current is produced parallel to the magnetic field. All these relate to the electric dipole moment of quark gluon plasma, P and CP violation, and the E.B term which has no effect in classical electromagnetism. Modification of the hydrodynamic equations for incorporation of the axial anomaly is also considered along with the calculation of the new kinetic coefficient appearing with the additional term of vorticity added to the current.

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