Non-Standard Physics in Leptonic and Semileptonic Decays of Charmed Mesons

Abstract

Recent measurements of the branching fraction for D_s -> l nu disagree with the Standard Model expectation, which relies on calculations of $f_{D_s}$ from lattice QCD. This paper uses recent preliminary measurements from CLEO and a new preliminary lattice-QCD result from this conference to update the significance of the discrepancy. The "f_{D_s} puzzle" stands now at 3.5sigma, with sigma predominantly from the statistical uncertainty of the experiments. New physics scenarios that could solve the puzzle would also lead to non-Standard amplitudes mediating the semileptonic decays D -> K l nu. This paper shows where the new amplitudes enter the differential rate and outlines where lattice QCD calculations are needed to confront recent and forthcoming measurements.

arXiv comment9 pp. Parallel talk at Lattice 2008. arXiv version includes appendix with more details on BSM semileptonic amplitude and rate

References in corpus (9)

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• The QCD spectrum with three quark flavors
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