Analyticity in theta on the lattice and the large volume limit of the topological susceptibility

Abstract

Non-analyticity of QCD with a θterm at θ=0 may signal a spontaneous breaking of both parity and time reversal invariance. We address this issue by investigating the large volume limit of the topological susceptibility $\chi$ in pure SU(3) gauge theory. We obtain an upper bound for the symmetry breaking order parameter <Q> and, as a byproduct, the value χ=(173.4(+/- 0.5)(+/- 1.2)(+1.1 / -0.2) MeV)^4 at β=6 (a approx= 0.1 fermi). The errors are the statistical error from our data, the one derived from the value used for Λ_L and an estimate of the systematic error respectively.

15 pages, corrected typos, added 1 reference, minor changes in text