Accumulating evidence for nonstandard leptonic decays of Ds mesons

The measured rate for D-s(+)--> l(+)nu decays, where l is a muon or tau, is larger than the standard model prediction, which relies on lattice QCD, at the 3.8 sigma level. We discuss how robust the theoretical prediction is, and we show that the discrepancy with experiment may be explained by a charged Higgs boson or a leptoquark.