U(2)xU(2)-symmetric fixed point from the Functional Renormalization   Group
  The existence of an U(2)xU(2)-symmetric fixed point in the chiral linear sigma model is confirmed using the Functional Renormalization Group (FRG). Its stability properties and the implications for the order of the chiral phase transition of two-flavor quantum chromodynamics (QCD) are discussed. Furthermore, several technical conclusions are drawn from the comparison with the results of resummed loop expansions. 
Mara Grahl
hep-th hep-ph