Recovering the chiral critical endpoint via delocalization of quark interactions

Abstract

We show that for the lower branch of the quark condensate and values higher than approximately $\ensuremath{-}(250\text{ }\text{ }\text{MeV}{)}^{3}$ the chiral critical endpoint in the Nambu--Jona-Lasinio model does not occur in the phase diagram. By using lattice motivated nonlocal quark interactions, we demonstrate that the critical endpoint can be recovered. We study this behavior for a range of condensate values and find that the variation in the position of the critical endpoint is more pronounced as the condensate is increased.