New high-precision $b$, $c$, and $s$ masses from pseudoscalar-pseudoscalar correlators in $n_f=4$ lattice QCD

We extend an earlier lattice QCD analysis of heavy-quark current-current correlators to obtain new values for the $\overline{\mathrm{MS}}$ masses of the $b$, $c$, and $s$ quarks. The analysis uses gluon configurations from the MILC collaboration with vacuum polarization contributions from $u$, $d$, $s$, and $c$ quarks ($n_f=4$), and lattice spacings down to 0.032 fm. We find that $\overline{m}_b(\overline{m}_b,n_f=5) = 4.1911(62)$ GeV, $\overline{m}_c(3 \mathrm{GeV},n_f=4) = 0.9808(33)$ GeV, and $\overline{m}_s(3 \mathrm{GeV},n_f=4) = 83.34(26)$ MeV. These results are corrected for QED by including (quenched) QED in the simulations. They are among the most accurate values by any method to date. We give a detailed analysis of finite lattice-spacing errors that shows why the HISQ discretization of the quark action is particularly useful for $b$-quark simulations even for lattices where $am_b\approx1$. We also calculate QED and isospin corrections to the (fictitious) $η_s$-meson mass, which is used to tune $s$-quark masses in lattice simulations.