An estimate of the chiral condensate from unquenched lattice QCD

Abstract

Using the parameters in the chiral Lagrangian obtained by MILC from their unquenched lattice QCD calculations with 2+1 flavours of sea quarks, I estimate <psi_bar psi> (2 GeV)/n_f = -(259 \pm 27 MeV)**3 in the MS_bar scheme. I compare this value to other determinations.

Comments: 8 pages. No figures. Version published in Phys.Lett.B. No change in results, but some parts of the text changed. Additional references added