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Scheme variations of the QCD coupling

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Autor(es):
Boito, Diogo ; Jamin, Matthias ; Miravitllas, Ramon ; Foka, Y ; Brambilla, N ; Kovalenko, V
Número total de Autores: 6
Tipo de documento: Artigo Científico
Fonte: RICAP16, 6TH ROMA INTERNATIONAL CONFERENCE ON ASTROPARTICLE PHYSICS; v. 137, p. 10-pg., 2017-01-01.
Resumo

The Quantum Chromodynamics (QCD) coupling alpha(s) is a central parameter in the Standard Model of particle physics. However, it depends on theoretical conventions related to renormalisation and hence is not an observable quantity. In order to capture this dependence in a transparent way, a novel definition of the QCD coupling, denoted by (a) over cap, is introduced, whose running is explicitly renormalisation scheme invariant. The remaining renormalisation scheme dependence is related to transformations of the QCD scale Lambda, and can be parametrised by a single parameter C. Hence, we call (a) over cap a the C-scheme coupling. The dependence on C can be exploited to study and improve perturbative predictions of physical observables. This is demonstrated for the QCD Adler function and hadronic decays of the tau lepton. (AU)

Processo FAPESP: 15/20689-9 - Determinação precisa de parâmetros fundamentais da QCD
Beneficiário:Diogo Rodrigues Boito
Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores