Flux tubes in full QCD at high temperature

Abstract

Chromoelectric and chromomagnetic field and energy density distributions produced by a quark-antiquark pair have been investigated in the presence of dynamical fermions in the close vicinity to the deconfinement phase transition. In our lattice simulation we have used highly improved staggered quark action and tree level improved Symanzik gauge (HISQ/tree) action on the lattices of two different sizes, exploiting the Gradient flow method for noise reduction. We find that, in full QCD with dynamical quarks, the dynamical fermions widen the flux tube in a short separation range of about R = 1 fm, after which an hadronization takes place due to the suppression by the dynamical fermions. Energy density and width of the flux tube vanish at about R = 1.8 fm and R = 1.5 fm, respectively, at all temperatures. The present results also suggest that the flux tube structure still persists in the deconfined phase and it melts gradually after certain temperature value is reached above the critical temperature.