High-precision quark masses and QCD coupling from nf=4 lattice QCD

Chakraborty, B., Davies, C.T.H. , Galloway, B., Knecht, P., Koponen, J., Donald, G.C., Dowdall, R.J., Lepage, G.P. and McNeile, C. (2015) High-precision quark masses and QCD coupling from nf=4 lattice QCD. Physical Review D, 91(5), 054508. (doi: 10.1103/PhysRevD.91.054508)

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Abstract

We present a new lattice QCD analysis of heavy-quark pseudoscalar-pseudoscalar correlators, using gluon configurations from the MILC Collaboration that include vacuum polarization from u, d, s, and c quarks (nf=4). We extract new values for the QCD coupling and for the c quark’s MS¯¯¯¯¯ mass: αMS¯¯¯¯¯(MZ,nf=5)=0.11822(74) and mc(3  GeV,nf=4)=0.9851(63)  GeV. These agree well with our earlier simulations using nf=3 sea quarks, vindicating the perturbative treatment of c quarks in that analysis. We also obtain a new nonperturbative result for the ratio of c and s quark masses: mc/ms=11.652(65). This ratio implies ms(2  GeV,nf=3)=93.6(8)  MeV when it is combined with our new c mass. Combining mc/ms with our earlier mb/mc gives mb/ms=52.55(55), which is several standard deviations (but only 4%) away from the Georgi-Jarlskop prediction from certain grand unified theories. Finally we obtain an nf=4 estimate for mb/mc=4.528(54) which agrees well with our earlier nf=3 result. The new ratio implies mb(mb,nf=5)=4.162(48)  GeV.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Galloway, Mr Ben and Davies, Professor Christine and Donald, Dr Gordon and McNeile, Dr Craig and Koponen, Dr Jonna and Dowdall, Dr Rachel
Authors: Chakraborty, B., Davies, C.T.H., Galloway, B., Knecht, P., Koponen, J., Donald, G.C., Dowdall, R.J., Lepage, G.P., and McNeile, C.
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(5):054508
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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