A Measurement of $\mathcal{B}(D_s\to \varphi l^{+}\nu )/calB(D_s\to \varphi {\pi }^{+})$

Abstract

Using the CLEO~II detector at CESR, we have measured the ratio of branching fractions $\mathcal{B}(D_s^{+}\to \varphi e^{+}\nu )/\mathcal{B}(D_s^{+}\to \varphi {\pi }^{+})=0.54\pm 0.05\pm 0.04$. We use this measurement to obtain a model dependent estimate of $\mathcal{B}(D_s^{+}\to \varphi {\pi }^{+})$.

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