Accessing the topological susceptibility via the Gribov horizon
نویسندگان
چکیده
The topological susceptibility, χ, following the work of Witten and Veneziano, plays a key role in identifying the relative magnitude of the η′ mass, the so-called U(1)A problem. A nonzero χ 4 is caused by the Veneziano ghost, the occurrence of an unphysical massless pole in the correlation function of the topological current Kμ. In a recent paper, [1], an explicit relationship between this Veneziano ghost and color confinement was proposed, by connecting the dynamics of the Veneziano ghost, and thus the topological susceptibility, with Gribov copies. However, the analysis of [1] is incompatible with BRST symmetry [2]. In this paper, we investigate the topological susceptibility, χ, in SU(3) and SU(2) Euclidean Yang-Mills theory using an appropriate Padé approximation tool and a non-perturbative gluon propagator, within a BRST invariant framework and by taking into account Gribov copies in a general linear covariant gauge.
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