Search for D to phi l nu and measurement of the branching fraction for D to phi pi

Abstract

Using a data sample of integrated luminosity of about 33 pb${}^{-1}$ collected around 3.773 GeV with the BESII detector at the BEPC collider, the semileptonic decays $D^{+}\to \varphi e^{+}{\nu }_e$, $D^{+}\to \varphi {\mu }^{+}{\nu }_{\mu }$ and the hadronic decay $D^{+}\to \varphi {\pi }^{+}$ are studied. The upper limits of the branching fractions are set to be $BF(D^{+}\to \varphi e^{+}{\nu }_e)<$ 2.01% and $BF(D^{+}\to \varphi {\mu }^{+}{\nu }_{\mu })<$ 2.04% at the 90% confidence level. The ratio of the branching fractions for $D^{+}\to \varphi {\pi }^{+}$ relative to $D^{+}\to K^{-}{\pi }^{+}{\pi }^{+}$ is measured to be $0.057\pm 0.011\pm 0.003$. In addition, the branching fraction for $D^{+}\to \varphi {\pi }^{+}$ is obtained to be $(5.2\pm 1.0\pm 0.4)\times 10^{-3}$.

6 pages, 5 figures, to be published in Eur.Phys.J.C