Experimental Determination of the QCD Effective Charge αg1(Q)

The QCD effective charge <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><...

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Main Authors:	Alexandre Deur, Volker Burkert, Jian-Ping Chen, Wolfgang Korsch
Format:	Article
Language:	English
Published:	MDPI AG 2022-05-01
Series:	Particles
Subjects:	strong interaction QCD nonperturbative running coupling constant hadrons nucleon
Online Access:	https://www.mdpi.com/2571-712X/5/2/15

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author	Alexandre Deur Volker Burkert Jian-Ping Chen Wolfgang Korsch
author_facet	Alexandre Deur Volker Burkert Jian-Ping Chen Wolfgang Korsch
author_sort	Alexandre Deur
collection	DOAJ
description	The QCD effective charge <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> is an observable that characterizes the magnitude of the strong interaction. At high momentum <i>Q</i>, it coincides with the QCD running coupling <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><mi mathvariant="normal">s</mi></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. At low <i>Q</i>, it offers a nonperturbative definition of the running coupling. We have extracted <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> from measurements carried out at Jefferson Lab that span the very low to moderately high <i>Q</i> domain, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.14</mn><mo>≤</mo><mi>Q</mi><mo>≤</mo><mn>2.18</mn></mrow></semantics></math></inline-formula> GeV. The precision of the new results is much improved over the previous extractions and the reach in <i>Q</i> at the lower end is significantly expanded. The data show that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> becomes <i>Q</i>-independent at very low <i>Q</i>. They compare well with two recent predictions of the QCD effective charge based on Dyson–Schwinger equations and on the AdS/CFT duality.
first_indexed	2024-03-09T22:49:18Z
format	Article
id	doaj.art-4f9081638cfc48eab8f21eeff65696b7
institution	Directory Open Access Journal
issn	2571-712X
language	English
last_indexed	2024-03-09T22:49:18Z
publishDate	2022-05-01
publisher	MDPI AG
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series	Particles
spelling	doaj.art-4f9081638cfc48eab8f21eeff65696b72023-11-23T18:23:56ZengMDPI AGParticles2571-712X2022-05-015217117910.3390/particles5020015Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)Alexandre Deur0Volker Burkert1Jian-Ping Chen2Wolfgang Korsch3Thomas Jefferson National Accelerator Facility, Physics Division, Newport News, VA 23606, USAThomas Jefferson National Accelerator Facility, Physics Division, Newport News, VA 23606, USAThomas Jefferson National Accelerator Facility, Physics Division, Newport News, VA 23606, USADepartment of Physics & Astronomy, University of Kentucky, Lexington, KY 40506, USAThe QCD effective charge <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> is an observable that characterizes the magnitude of the strong interaction. At high momentum <i>Q</i>, it coincides with the QCD running coupling <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><mi mathvariant="normal">s</mi></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. At low <i>Q</i>, it offers a nonperturbative definition of the running coupling. We have extracted <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> from measurements carried out at Jefferson Lab that span the very low to moderately high <i>Q</i> domain, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>0.14</mn><mo>≤</mo><mi>Q</mi><mo>≤</mo><mn>2.18</mn></mrow></semantics></math></inline-formula> GeV. The precision of the new results is much improved over the previous extractions and the reach in <i>Q</i> at the lower end is significantly expanded. The data show that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>α</mi><msub><mi>g</mi><mn>1</mn></msub></msub><mrow><mo>(</mo><mi>Q</mi><mo>)</mo></mrow></mrow></semantics></math></inline-formula> becomes <i>Q</i>-independent at very low <i>Q</i>. They compare well with two recent predictions of the QCD effective charge based on Dyson–Schwinger equations and on the AdS/CFT duality.https://www.mdpi.com/2571-712X/5/2/15strong interactionQCDnonperturbativerunning coupling constanthadronsnucleon
spellingShingle	Alexandre Deur Volker Burkert Jian-Ping Chen Wolfgang Korsch Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>) Particles strong interaction QCD nonperturbative running coupling constant hadrons nucleon
title	Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)
title_full	Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)
title_fullStr	Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)
title_full_unstemmed	Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)
title_short	Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)
title_sort	experimental determination of the qcd effective charge i α i sub i g i 1 sub i q i
topic	strong interaction QCD nonperturbative running coupling constant hadrons nucleon
url	https://www.mdpi.com/2571-712X/5/2/15
work_keys_str_mv	AT alexandredeur experimentaldeterminationoftheqcdeffectivechargeiaisubigi1subiqi AT volkerburkert experimentaldeterminationoftheqcdeffectivechargeiaisubigi1subiqi AT jianpingchen experimentaldeterminationoftheqcdeffectivechargeiaisubigi1subiqi AT wolfgangkorsch experimentaldeterminationoftheqcdeffectivechargeiaisubigi1subiqi

Experimental Determination of the QCD Effective Charge <i>α</i><sub><i>g</i>1</sub>(<i>Q</i>)

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