VA\tilde V correlator within the instanton vacuum model
Abstract
The correlator of vector and nonsinglet axial-vector currents in the external electromagnetic field is calculated within the instanton liquid model of QCD vacuum. In general the correlator has two Lorentz structures: longitudinal w_L and transversal w_T with respect to axial-vector index. Within the instanton model the saturation of the anomalous w_L structure is demonstrated. It is known that in the chiral limit the transversal structure w_T is free from perturbative corrections. In this limit within the instanton model we calculate the transversal invariant function w_T at arbitrary momentum transfer, q, and show the absence of power corrections to this structure at large q^2. Instead there arise the exponential corrections to w_T at large q^2 reflecting nonlocal properties of QCD vacuum. The slope of w_T at zero virtuality, the QCD vacuum magnetic susceptibility of the quark condensate and its momentum dependence are estimated.
Cite
@article{arxiv.hep-ph/0505007,
title = {VA\tilde V correlator within the instanton vacuum model},
author = {A. E. Dorokhov},
journal= {arXiv preprint arXiv:hep-ph/0505007},
year = {2009}
}
Comments
16 pages, 7 figures (revised version, some typos are corrected)