Physics Colloquium, May 22, 2012
Are Heavy Ion Collisions Strongly or Weakly Coupled? Yuri Kovchegov

The Ohio State University

I will review our recent efforts to understand the physics of heavy ion collisions, which resulted in the following conundrum. On the one hand, many of the observables, such as the number of particles produced in the collision, are best described by the weakly-coupled calculations in quantum chromodynamics (QCD), based on Feynman diagrams. On the other hand, another large number of observables, including the observable called "elliptic flow", are well-described by hydrodynamic simulations with a low specific shear viscosity, as expected for a strongly-coupled medium from the calculations based on Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence. This raises a question: are the heavy ion collisions strongly or weakly coupled? I will present my take on the possible resolution of this conundrum.

Dr. Kovchegov's Web Site

4:00 p.m., Physics Research Building (PRB), Room 1080

Reception at 3:45 p.m., Atrium, PRB