Strong coupling from an improved tau vector isovector spectral function

Autor(es)

Boito, Diogo ; Golterman, Maarten ; Maltman, Kim ; Peris, Santiago ; Rodrigues, Marcus, V ; Schaaf, Wilder

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW D; v. 103, n. 3, p. 24-pg., 2021-02-26.

Resumo

We combine ALEPH and OPAL results for the spectral distributions measured in tau -> pi(-) pi(0)nu(tau), tau -> 2 pi(-) pi(+) pi(0)nu(tau) and tau -> pi(-) 3 pi(0)nu(tau) decays with (i) recent BABAR results for the analogous tau -> K- K-0 nu(tau) distribution and (ii) estimates of the contributions from other hadronic tau-decay modes obtained using CVC and electroproduction data, to obtain a new and more precise nonstrange, inclusive vector, isovector spectral function. The BABAR K- K-0 and CVC/electroproduction results provide us with alternate, entirely data-based input for the contributions of all exclusive modes for which ALEPH and OPAL employed Monte-Carlo-based estimates. We use the resulting spectral function to determine alpha(s)(m(tau)), the strong coupling at the tau mass scale, employing finite energy sum rules. Using the fixed-order perturbation theory (FOPT) prescription, we find alpha(s)(m(tau)) = 0.3077 +/- 0.0075, which corresponds to the five-flavor result alpha(s)(M-Z) = 0.1171 +/- 0.0010 at the Z mass. While we also provide an estimate using contour-improved perturbation theory (CIPT), we point out that the FOPT prescription is to be preferred for comparison with other alpha(s) determinations employing the (MS) over bar scheme, especially given the inconsistency between CIPT and the standard operator product expansion recently pointed out in the literature. Additional experimental input on the dominant 2 pi and 4 pi modes would allow for further improvements to the current analysis. (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
• Processo FAPESP: 19/16957-9 - Determinação precisa da massa do quark C
• Beneficiário: Marcus Vinícius Gonzalez Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Mestrado