When more than one numbers is quoted, I use MS scheme values for the most complete model. I also quote the comparable PDG values, which are consistent with the FLAG values, except as noted in bold.
* Up quark mass at 2 GeV = 2.14(8) MeV
(PDG is 2.16 + 0.49-0.26 MeV)
3.7% relative uncertainty
* Down quark mass at 2 GeV = 4.70(5) MeV
1% relative uncertainty
(PDG is 4.67 + 0.48-0.17 MeV)
* Strange quark mass at 2 GeV = 93.44(68) MeV
0.7% relative uncertainty
(PDG is 93 + 11 - 5 MeV)
* Charm quark mass at c quark energy = 1278(13) MeV
0.1% relative uncertainty
(PDG is 1,270 ± 20 MeV)
* Bottom quark mass at b quark energy = 4203(11) MeV
0.26% relative uncertainty
(PDG is 4,180 + 30 -20 MeV)
* Average of up and down quark mass at 2 GeV = 3.410(43) MeV
1.26% relative uncertainty
(PDG is 3.45 + 0.55 -0.15 MeV)
* Ratio of up quark to down quark mass = 0.465(24)
5.16% relative uncertainty
(PDG is 0.47 + 0.06 - 0.07)
* Ratio of strange quark mass to average of up and down quark mass = 27.23 (10)
0.37% relative uncertainty
(PDG is 27.3 + 0.7 -1.3)
* Ratio of c quark mass to s quark mass = 11.768(34)
0.29% relative uncertainty
(PDG is 11.72 ± 0.25)
A technical detail regarding the quark masses
FLAG also quotes masses for the Renormalization Group Independent (RGI) scheme, which is arguably a better benchmark. But this scheme is less familiar and less useful for comparisons from other sources, so I omit them here. Generally, speaking those results are approximately proportionately more massive.
CKM Matrix Elements
FLAG also updated is CKM matrix element values determined individually (as opposed to with global SM fits):
* V(us) = 0.2248(7)
The consistent stand alone PDG value is 0.2245(8). The PDG global fit value is 0.22650(48) which is in 2.4σ tension with the FLAG result.
Treating the discrepancy as true uncertainty, however, the relative uncertainty is still about 0.7%.
* V(ud) = 0.97440(17).
This compared to a stand alone PDG value of 0.97370(14) which differs by ≈ 3.2σ from the FLAG value. The PDG global fit value is 0.97401(11) which is consistent with the FLAG value.
Treating the discrepancy as true uncertainty, however, the relative uncertainty is still about 0.07%.
Strong Force Coupling Constant
FLAG updates its estimate of the strong force coupling constant value, at the Z boson mass, in five flavor QCD:
* α(s) = 0.1184(8).
0.68% relative uncertainty
The PDG is 0.1179(10).
My Summary From June 4, 2021