QCD chiral symmetry restoration with a large number of quarks in a model   with a confining propagator and dynamically massive gluons
  Considering a QCD chiral symmetry breaking model where the gap equation contains an effective confining propagator and a dressed gluon propagator with a dynamically generated mass, we verify that the chiral symmetry is restored for a large number of quarks $n_{f}\approx 7-13$. We discuss the uncertainty in the results, that is related to the determination of the string tension ($K_{F}$), appearing in the confining propagator, and the effective gluon mass ($m_{g}$) at large $n_{f}$. 
R. M. Capdevilla, A. Doff and A. A. Natale
hep-ph