Highprecision quark masses and QCD coupling from n_{f}=4 lattice QCD
Abstract
We present a new lattice QCD analysis of heavyquark pseudoscalarpseudoscalar correlators, using gluon configurations from the MILC Collaboration that include vacuum polarization from u , d , s , and c quarks (n_{f}=4 ). We extract new values for the QCD coupling and for the c quark's MS ¯ mass: α_{MS ¯}(M_{Z},n_{f}=5 )=0.11822 (74 ) and m_{c}(3 GeV ,n_{f}=4 )=0.9851 (63 ) GeV . These agree well with our earlier simulations using n_{f}=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: m_{c}/m_{s}=11.652 (65 ). This ratio implies m_{s}(2 GeV ,n_{f}=3 )=93.6 (8 ) MeV when it is combined with our new c mass. Combining m_{c}/m_{s} with our earlier m_{b}/m_{c} gives m_{b}/m_{s}=52.55 (55 ), which is several standard deviations (but only 4%) away from the GeorgiJarlskop prediction from certain grand unified theories. Finally we obtain an n_{f}=4 estimate for m_{b}/m_{c}=4.528 (54 ) which agrees well with our earlier n_{f}=3 result. The new ratio implies m_{b}(m_{b},n_{f}=5 )=4.162 (48 ) GeV .
 Publication:

Physical Review D
 Pub Date:
 March 2015
 DOI:
 10.1103/PhysRevD.91.054508
 arXiv:
 arXiv:1408.4169
 Bibcode:
 2015PhRvD..91e4508C
 Keywords:

 11.15.Ha;
 12.38.Aw;
 12.38.Gc;
 Lattice gauge theory;
 General properties of QCD;
 Lattice QCD calculations;
 High Energy Physics  Lattice
 EPrint:
 16 pages, 9 figures, 6 tables