2014/07/18 by M. G. Ryskin, Ryskin, M. G., V. A. Sadovnikova +1
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #hep-ph
paper · pdf · doi:10.48550/arxiv.1407.4967
16 pages, 2 figures. arXiv admin note: text overlap with arXiv:1407.2749
arxiv created 2014/07/18 · arxiv updated 2014/07/21
We emphasize the role of the x dependence of the quark condensate <| q(0)q(x)|> originated by the zero fermion modes in the instanton vacuum. The effect is not negligible since the inverse size of the instanton 1/ρ~600MeV is comparable with the value of Borel mass M~1GeV. Using as an example the sum rules for the nucleon we show that this "non-locality" may strongly affected the conventional results obtained under the <| q(0)q(x)|>=<| q(0)q(0)|> approximation.