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 $${\overline{\...
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doaj-199f490a37d14440b78ec8c6211be2972020-11-25T01:56:06ZengSpringerOpenEuropean Physical Journal C: Particles and Fields1434-60441434-60522018-12-01781212510.1140/epjc/s10052-018-6490-9Bjorken polarized sum rule and infrared-safe QCD couplingsCésar Ayala0Gorazd Cvetič1Anatoly V. Kotikov2Binur G. Shaikhatdenov3Department of Physics, Universidad Técnica Federico Santa María (UTFSM)Department of Physics, Universidad Técnica Federico Santa María (UTFSM)Joint Institute for Nuclear ResearchJoint Institute for Nuclear ResearchAbstract Experimental data obtained for the polarized Bjorken sum rule (BSR) $$\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 |
work_keys_str_mv |
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