Determination of the strong coupling constant from the charmonium spectrum

Lattice gauge theory techniques have recently achieved sufficient accuracy to permit a determination of the strong coupling constant from the 1{ital P}-1{ital S} splitting in the charmonium system, with all systematic errors estimated quantitatively. The present result is {alpha}{sub M{bar S}}(5 GeV)=0.174{plus minus}0.012, or equivalently, {Lambda}{sub M{bar S}}{sup (4)}=160{sub {minus}37}{sup +47} MeV ({ital M{bar S}} denotes the modified minimal subtraction scheme).