Bjorken polarized sum rule and infrared-safe QCD couplings

Abstract Experimental data obtained for the polarized Bjorken sum rule (BSR) $$\Gamma _1^{p-n}(Q^2)$$ Γ1p-n(Q2) are fitted by using predictions derived within a truncated operator product expansion (OPE) approach to QCD. Four QCD versions are considered: perturbative QCD (pQCD) in the $${\overline{\...

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Main Authors: César Ayala, Gorazd Cvetič, Anatoly V. Kotikov, Binur G. Shaikhatdenov
Format: Article
Language:English
Published: SpringerOpen 2018-12-01
Series:European Physical Journal C: Particles and Fields
Online Access:http://link.springer.com/article/10.1140/epjc/s10052-018-6490-9
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spelling doaj-199f490a37d14440b78ec8c6211be2972020-11-25T01:56:06ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522018-12-01781212510.1140/epjc/s10052-018-6490-9Bjorken polarized sum rule and infrared-safe QCD couplingsCésar Ayala0Gorazd Cvetič1Anatoly V. Kotikov2Binur G. Shaikhatdenov3Department of Physics, Universidad Técnica Federico Santa María (UTFSM)Department of Physics, Universidad Técnica Federico Santa María (UTFSM)Joint Institute for Nuclear ResearchJoint Institute for Nuclear ResearchAbstract Experimental data obtained for the polarized Bjorken sum rule (BSR) $$\Gamma _1^{p-n}(Q^2)$$ Γ1p-n(Q2) are fitted by using predictions derived within a truncated operator product expansion (OPE) approach to QCD. Four QCD versions are considered: perturbative QCD (pQCD) in the $${\overline{\mathrm{MS}}}$$ MS¯ scheme, Analytic Perturbation Theory (APT), and 2$$\delta $$ δ and 3$$\delta $$ δ analytic QCD versions. In contrast to pQCD, these QCD variants do not have Landau singularities at low positive $$Q^2$$ Q2 , which facilitates the fitting procedure significantly. The fitting procedure is applied first to the experimental data of the inelastic part of BSR, and the known elastic contributions are added after the fitting. In general, when 2$$\delta $$ δ and 3$$\delta $$ δ QCD coupling is used the fitted curves give the best results, within the $$Q^2$$ Q2 -range of the fit as well as in extended $$Q^2$$ Q2 -intervals. When the fitting procedure is applied to the total BSR, i.e., to the sum of the experimental data and the elastic contribution, the quality of the results deteriorates significantly.http://link.springer.com/article/10.1140/epjc/s10052-018-6490-9
collection DOAJ
language English
format Article
sources DOAJ
author César Ayala
Gorazd Cvetič
Anatoly V. Kotikov
Binur G. Shaikhatdenov
spellingShingle César Ayala
Gorazd Cvetič
Anatoly V. Kotikov
Binur G. Shaikhatdenov
Bjorken polarized sum rule and infrared-safe QCD couplings
European Physical Journal C: Particles and Fields
author_facet César Ayala
Gorazd Cvetič
Anatoly V. Kotikov
Binur G. Shaikhatdenov
author_sort César Ayala
title Bjorken polarized sum rule and infrared-safe QCD couplings
title_short Bjorken polarized sum rule and infrared-safe QCD couplings
title_full Bjorken polarized sum rule and infrared-safe QCD couplings
title_fullStr Bjorken polarized sum rule and infrared-safe QCD couplings
title_full_unstemmed Bjorken polarized sum rule and infrared-safe QCD couplings
title_sort bjorken polarized sum rule and infrared-safe qcd couplings
publisher SpringerOpen
series European Physical Journal C: Particles and Fields
issn 1434-6044
1434-6052
publishDate 2018-12-01
description Abstract Experimental data obtained for the polarized Bjorken sum rule (BSR) $$\Gamma _1^{p-n}(Q^2)$$ Γ1p-n(Q2) are fitted by using predictions derived within a truncated operator product expansion (OPE) approach to QCD. Four QCD versions are considered: perturbative QCD (pQCD) in the $${\overline{\mathrm{MS}}}$$ MS¯ scheme, Analytic Perturbation Theory (APT), and 2$$\delta $$ δ and 3$$\delta $$ δ analytic QCD versions. In contrast to pQCD, these QCD variants do not have Landau singularities at low positive $$Q^2$$ Q2 , which facilitates the fitting procedure significantly. The fitting procedure is applied first to the experimental data of the inelastic part of BSR, and the known elastic contributions are added after the fitting. In general, when 2$$\delta $$ δ and 3$$\delta $$ δ QCD coupling is used the fitted curves give the best results, within the $$Q^2$$ Q2 -range of the fit as well as in extended $$Q^2$$ Q2 -intervals. When the fitting procedure is applied to the total BSR, i.e., to the sum of the experimental data and the elastic contribution, the quality of the results deteriorates significantly.
url http://link.springer.com/article/10.1140/epjc/s10052-018-6490-9
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