Achieving renormalization–scale– and scheme–independence in Padé–related resummation in QCD
نویسنده
چکیده
Previously developed Padé–related method of resummation for QCD observables, which achieves exact renormalization–scale–invariance, is extended so that the scheme–invariance is obtained as well. The dependence on the leading scheme parameter c2 is eliminated by a variant of the method of the principle of minimal sensitivity. The subleading parameter c3 in the approximant is then fixed in such a way that the correct known location of the leading infrared renormalon pole is reproduced. The pertaining β–functions in the approximant are quasianalytically continued by Padé approximants. Two aspects of nonperturbative physics are accounted for in the presented resummation: a mechanism of quasianalytic continuation from the weak– into the strong–coupling regime, and the (approximant–specific) contribution of the leading infrared renormalon. The case of the Bjorken polarized sum rule is considered as a specific example of how the method works. PACS number(s): 11.10.Hi, 11.80.Fv, 12.38.Bx, 12.38.Cy
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