Search for the decay D+--> micro+ nu micro and an upper limit on the pseudoscalar decay constant.

Abstract

We report the results of a search for the leptonic decay D+→μ+νμ using the Mark III detector at the SLAC e+e− storage ring SPEAR. A data sample of 9.3 pb−1 collected at the ψ(3770) resonance yields no signal events, corresponding to a 90%-confidence-level upper limit of 7.2×10−4 on the branching ratio B(D+→μ+νμ). This represents an upper limit on the pseudoscalar decay constant fD of 290 MeV/c2.Received 13 October 1987DOI:https://doi.org/10.1103/PhysRevLett.60.1375©1988 American Physical Society