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Infrared renormalons and power suppressed effects in e+e- jet events
We study the effect of infrared renormalons upon shape variables that are commonly used to determine the strong coupling constant in e^+e^- annihilation into hadronic jets. We consider the model of QCD in the limit of large n_f. We find a wide variety of different behaviours of shape variables with...
Autores principales: | , |
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Lenguaje: | eng |
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1995
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Materias: | |
Acceso en línea: | https://dx.doi.org/10.1016/0550-3213(95)00461-Z http://cds.cern.ch/record/283249 |
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author | Nason, P Seymour, Michael H |
author_facet | Nason, P Seymour, Michael H |
author_sort | Nason, P |
collection | CERN |
description | We study the effect of infrared renormalons upon shape variables that are commonly used to determine the strong coupling constant in e^+e^- annihilation into hadronic jets. We consider the model of QCD in the limit of large n_f. We find a wide variety of different behaviours of shape variables with respect to power suppressed effects induced by infrared renormalons. In particular, we find that oblateness is affected by 1/Q non--perturbative effects even away from the two jet region, and the energy--energy correlation is affected by 1/Q non--perturbative effects for all values of the angle. On the contrary, variables like thrust, the c parameter, the heavy jet mass, and others, do not develop any 1/Q correction away from the two jet region at the leading n_f level. We argue that 1/Q corrections will eventually arise at subleading n_f level, but that they could maintain an extra \as(Q) suppression. We conjecture therefore that the leading power correction to shape variables will have in general the form \alpha^n_{\rm S}(Q)/Q, and it may therefore be possible to classify shape variables according to the value of n. |
id | cern-283249 |
institution | Organización Europea para la Investigación Nuclear |
language | eng |
publishDate | 1995 |
record_format | invenio |
spelling | cern-2832492019-09-30T06:29:59Zdoi:10.1016/0550-3213(95)00461-Zhttp://cds.cern.ch/record/283249engNason, PSeymour, Michael HInfrared renormalons and power suppressed effects in e+e- jet eventsParticle Physics - PhenomenologyWe study the effect of infrared renormalons upon shape variables that are commonly used to determine the strong coupling constant in e^+e^- annihilation into hadronic jets. We consider the model of QCD in the limit of large n_f. We find a wide variety of different behaviours of shape variables with respect to power suppressed effects induced by infrared renormalons. In particular, we find that oblateness is affected by 1/Q non--perturbative effects even away from the two jet region, and the energy--energy correlation is affected by 1/Q non--perturbative effects for all values of the angle. On the contrary, variables like thrust, the c parameter, the heavy jet mass, and others, do not develop any 1/Q correction away from the two jet region at the leading n_f level. We argue that 1/Q corrections will eventually arise at subleading n_f level, but that they could maintain an extra \as(Q) suppression. We conjecture therefore that the leading power correction to shape variables will have in general the form \alpha^n_{\rm S}(Q)/Q, and it may therefore be possible to classify shape variables according to the value of n.hep-ph/9506317CERN-TH-95-150IFUM-507-FToai:cds.cern.ch:2832491995-06-13 |
spellingShingle | Particle Physics - Phenomenology Nason, P Seymour, Michael H Infrared renormalons and power suppressed effects in e+e- jet events |
title | Infrared renormalons and power suppressed effects in e+e- jet events |
title_full | Infrared renormalons and power suppressed effects in e+e- jet events |
title_fullStr | Infrared renormalons and power suppressed effects in e+e- jet events |
title_full_unstemmed | Infrared renormalons and power suppressed effects in e+e- jet events |
title_short | Infrared renormalons and power suppressed effects in e+e- jet events |
title_sort | infrared renormalons and power suppressed effects in e+e- jet events |
topic | Particle Physics - Phenomenology |
url | https://dx.doi.org/10.1016/0550-3213(95)00461-Z http://cds.cern.ch/record/283249 |
work_keys_str_mv | AT nasonp infraredrenormalonsandpowersuppressedeffectsineejetevents AT seymourmichaelh infraredrenormalonsandpowersuppressedeffectsineejetevents |