Use of the double dispersion relation in QCD sum rules with external fields
Abstract
In QCD sum rules with external fields, the double dispersion relation is often used to represent the correlation function. In this work, we point out that the double spectral density, when it is determined by successive applications of the Borel transformation, contains the spurious terms which should be kept in the subtraction terms in the double dispersion relation. They are zero under the Borel transformation but, if the dispersion integral is restricted with QCD duality, they contribute to the continuum. For the simple case with zero external momentum, it is shown that subtracting out the spurious terms is equivalent to the QCD sum rules represented by the single dispersion relation.
Keywords
Cite
@article{arxiv.nucl-th/9906081,
title = {Use of the double dispersion relation in QCD sum rules with external fields},
author = {Hungchong Kim},
journal= {arXiv preprint arXiv:nucl-th/9906081},
year = {2009}
}
Comments
10 pages, slightly revised, accepted for publication in Progress of Theoretical Physics