High-Precision c and b Masses, and QCD Coupling from Current-Current Correlators in Lattice and Continuum QCD

TL;DR

This paper provides highly precise determinations of the charm and bottom quark masses and the QCD coupling constant using lattice and continuum QCD methods, improving accuracy and consistency across different approaches.

Contribution

The study extends previous lattice-QCD analyses to smaller lattice spacings and larger masses, yielding the most accurate quark mass and coupling values to date, and introduces a new method for simplifying complex fits.

Findings

New precise values for m_c and m_b quark masses.

Updated QCD coupling constant alpha_s(M_Z).

Agreement between different mass determination methods within 1%.

Abstract

We extend our earlier lattice-QCD analysis of heavy-quark correlators to smaller lattice spacings and larger masses to obtain new values for the c mass and QCD coupling, and, for the first time, values for the b mass: m_c(3GeV,n_f=4)=0.986(6)GeV, alpha_msb(M_Z,n_f=5)=0.1183(7), and m_b(10GeV,n_f=5)=3.617(25)GeV. These are among the most accurate determinations by any method. We check our results using a nonperturbative determination of the mass ratio m_b(mu,n_f)/m_c(mu,n_f); the two methods agree to within our 1% errors and taken together imply m_b/m_c=4.51(4). We also update our previous analysis of alpha_msb from Wilson loops to account for revised values for r_1 and r_1/a, finding a new value alpha_\msb(M_Z,n_f=5)=0.1184(6); and we update our recent values for light-quark masses from the ratio m_c/m_s. Finally, in the Appendix, we derive a procedure for simplifying and accelerating complicated least-squares fits.