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QCD Sum Rules and the Lowest-Lying I=0 Scalar Resonance

V. Elias·A. H. Fariborz·Fang Shi·T. G. Steele
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Abstract

A QCD Laplace sum rule framework is employed to investigate the relationship between the mass and the decay width of the sigma, the lowest-lying isoscalar resonance in the spin-zero meson channel. Our analysis differs from prior analyses, not only by incorporating finite-width departures from the narrow resonance approximation, but also through the inclusion of direct-instanton contributions and three-loop-order perturbative effects. Assuming that the sigma is the dominant subcontinuum resonance in this channel, the least upper bound we obtain for the sigma-mass is shown to increase with the sigma-width, and suggests that a sigma lighter than 800 MeV should have a total width substantially smaller than its mass.

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V. Elias, A. H. Fariborz, Fang Shi, T. G. Steele. 1997-10-21. QCD Sum Rules and the Lowest-Lying I=0 Scalar Resonance. https://arxiv.org/abs/hep-ph/9708466

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