Leptonic decay-constant ratio f_{K^+}/f_{pi^+} from lattice QCD with physical light quarks

A. Bazavov, C. Bernard, C. DeTar +15

A calculation of the ratio of leptonic decay constants f_{K^+}/f_{π^+} makes possible a precise determination of the ratio of CKM matrix elements |V_{us}|/|V_{ud}| in the Standard…