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The 16\half-N_f Expansion and the Infrared Fixed Point in Perturbative QCD

P. M. Stevenson
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Abstract

In QCD with 16\half-epsilon massless quark flavours there is an infrared fixed point with alpha_s/pi = (8/321)epsilon in the limit epsilon -> 0+. I develop the idea of Banks and Zaks to expand about N_f=16\half. This expansion is certainly useful for N_f=16, 15, 14, ..., and arguably it can reach the phenomenologically interesting case N_f=2, where it suggests that alpha_s/pi "freezes" to a value of order of magnitude 0.4 in the infrared.

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P. M. Stevenson. 1994-05-03. The 16\half-N_f Expansion and the Infrared Fixed Point in Perturbative QCD. https://doi.org/10.1016/0370-2693(94)90962-8

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