Ultra-light Glueballs in Quark-Gluon Plasma

Abstract

We consider the dynamics of the scalar and pseudoscalar glueballs in the Quark-Gluon Plasma (QGP). By using the instanton model for the QCD vacuum we give the arguments that the nonperturbative gluon-gluon interaction is qualitatively different in the confinement and deconfinement phases. Based on this observation it is shown that above $T_c$ the values of the scalar and pseudoscalar glueball masses might be very small. The estimation of the temperature of scale invariance restoration, at which the scalar glueball becomes massless, is given. We also discuss the Bose-Einstein condensation of the glueballs and the superfluidity of the glueball matter in QGP.

Comments: 14 pages,6 figures, based on the talk given at APCTP-BLTP JINR Joint Workshop, 29 June-4 July 2014, Jeju Island, South Korea