Zusammenfassung
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 (n(f) = 4). We extract new values for the QCD coupling and for the c quark's (MS) over bar mass: alpha((MS) over bar)(M-Z, n(f) = 5) = 0.11822(74) and m(c)(3 GeV, n(f) = 4) = 0.9851(63) GeV. ...
Zusammenfassung
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 (n(f) = 4). We extract new values for the QCD coupling and for the c quark's (MS) over bar mass: alpha((MS) over bar)(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 Georgi-Jarlskop 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.
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