Restoration of chiral and U(1)_A symmetries in excited hadrons in the semiclassical regime

Abstract

Restoration of chiral and $U(1{)}_A$ symmetries in excited hadrons is reviewed. Implications of the OPE as well as of the semiclassical expansion for this phenomenon are discussed. A solvable model of the 't Hooft type in 3+1 dimensions is presented, which demonstrates a fast restoration of both chiral and $U(1{)}_A$ symmetries at larger spins and radial excitations.

Comments: 9 pp. Talk given at the seventh workshop "Continuous Advances in QCD 2006", Minneapolis, May 11-14, 2006