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.

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

References in corpus (7)

• Highly Improved Staggered Quarks on the Lattice, with Applications to Charm Physics
• High Precision determination of the pi, K, D and D_s decay constants from lattice QCD
• Accumulating evidence for nonstandard leptonic decays of D_s mesons
• Measurement of B(Ds -> munu)
• Leptoquarks in FCNC charm decays
• Decay Constants of Charged Pseudoscalar Mesons
• R-parity violating supersymmetry, B_s mixing, and D_s -> l nu