Gluon Condensate from Superconvergent QCD Sum Rule

TL;DR

This paper derives a superconvergent QCD sum rule for the vector current correlator to estimate the gluon condensate, emphasizing the dominance of bound states and low-energy cross sections in the nonperturbative regime.

Contribution

It introduces a superconvergent sum rule approach to determine the gluon condensate from the vector current correlator, highlighting a novel method for nonperturbative QCD analysis.

Findings

Estimated gluon condensate: 0.048 ± 0.039 GeV^4

Sum rule dominated by bound states and low-energy cross sections

Provides a new nonperturbative QCD sum rule technique

Abstract

Sum rules for the nonperturbative piece of correlators (specifically, the vector current correlator) are discussed. The sum rule subtracting the perturbative part is of the superconvergent type. Thus it is dominated by the bound states and low energy production cross section. It leads to a determination of the gluon condensate of $<\alpha_s G^2> = 0.048 \pm 0.039 GeV^4$