Υ and Υ′ leptonic widths, abμ, and mb from full lattice QCD

Colquhoun, B. , Dowdall, R. J., Davies, C. T. H. , Hornbostel, K. and Lepage, G. P. (2015) Υ and Υ′ leptonic widths, abμ, and mb from full lattice QCD. Physical Review D, 91(7), 074514. (doi: 10.1103/PhysRevD.91.074514)

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Abstract

We determine the decay rate to leptons of the ground-state ϒ meson and its first radial excitation in lattice QCD for the first time. We use radiatively improved nonrelativistic QCD for the b quarks and include u, d, s and c quarks in the sea with u=d masses down to their physical values. We find Γðϒ → eþe−Þ ¼ 1.19ð11Þ keV and Γðϒ0 → eþe−Þ ¼ 0.69ð9Þ keV, both in good agreement with experimental results. The decay constants we obtain are included in a summary plot of meson decay constants from lattice QCD given in the Conclusions. We also test time moments of the vector current-current correlator against values determined from the b-quark contribution to σðeþe− → hadronsÞ and calculate the b-quark piece of the hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, ab μ ¼ 0.271ð37Þ × 10−10. Finally we determine the b-quark mass, obtaining in the MS scheme, ¯ m¯ bðm¯ b; nf ¼ 5Þ ¼ 4.196ð23Þ GeV, the most accurate result from lattice QCD to date.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Colquhoun, Dr Brian and Dowdall, Dr Rachel and Davies, Professor Christine
Authors: Colquhoun, B., Dowdall, R. J., Davies, C. T. H., Hornbostel, K., and Lepage, G. P.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN:1550-7998
ISSN (Online):1550-2368
Copyright Holders:Copyright © 2015 American Physical Society
First Published:First published in Physical Review D 91(7):074514
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher.

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