Deconfinement critical point of lattice QCD with Nf=2 Wilson fermions

The SU(3) pure gauge theory exhibits a first-order thermal deconfinement transition due to spontaneous breaking of its global Z(3) center symmetry. When heavy dynamical quarks are added, this symmetry is broken explicitly and the transition weakens with decreasing quark mass until it disappears at a critical point. We compute the critical hopping parameter and the associated pion mass for lattice QCD with N-f = 2 degenerate standard Wilson fermions on N-t is an element of {6, 8, 10} lattices, corresponding to lattice spacings a = 0.12 fm, a = 0.09 fm, a = 0.07 fm, respectively. Significant cutoff effects are observed, with the first-order region growing as the lattice gets finer. While current lattices are still too coarse for a continuum extrapolation, we estimate m(pi)(c) approximate to 4 GeV with a remaining systematic error of similar to 20%. Our results allow us to assess the accuracy of the leading-order and next-to-leading-order hopping expanded fermion determinant used in the literature for various purposes. We also provide a detailed investigation of the statistics required for this type of calculation, which is useful for similar investigations of the chiral transition.

Automated summary

The addition of heavy dynamical quarks weakens the first-order thermal deconfinement transition in SU(3) pure gauge theory until it disappears. The critical hopping parameter and associated pion mass for lattice QCD have been calculated, with significant cutoff effects observed. The results allow for an assessment of the accuracy of the fermion determinant used in literature.