Demythification of electroproduction local duality and precocious scaling

• Published in: Annals of physics 1977-02, Vol.103 (2), p.315-353
• Main Authors: De Rújula, A, Georgi, Howard, David Politzer, H
• Format: Article
• Language: English
• ISSN: 0003-4916; 1096-035X
• DOI: 10.1016/S0003-4916(97)90003-8

In an effort to develop a quantitative check of asymptotically free color-gauge theories, we analyze the logarithmic corrections to ξ-scaling coming from anomalous dimensions and coefficient functions of twist-two operators and compare with electroproduction data for 1 ⩽ Q 2 ⩽ 16 GeV 2. Excellent agreement is obtained using g 2(2 GeV) 4π 2 = 0.17 for the effective quark-gluon coupling in the color-gauge theory. Effects of higher-twist operators are suppressed by powers of M 0 2 Q 2 . We use data from the resonance region to show M 0 ⋍ 400 MeV , in agreement with theoretical expectations. Our fit to νW 2 in the scaling region also describes the resonance region in the sense of Bloom-gilman local duality. We show that local duality is a consequence of the moment predictions obtained from the operator-product expansion in quantum chromodynamics. We resolve a paradox associated with local duality and spin-zero targets. Present measurements of R = σ L σ T at large x and Q 2 are systematically higher than our predictions.