Measurement of the Relative Branching Fraction ofϒ(4S)to Charged and NeutralB-Meson Pairs

Abstract

We analyze $9.7\times {10}^6$ $B\overline{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral $B$-meson pairs produced at the $\Upsilon \left(4S\right)$ resonance. We measure the rates for $B^0\to J/\psi K^{(*)0}$ and $B^{+}\to J/\psi K^{(*)+}$ decays and use the world-average $B$-meson lifetime ratio to extract the relative widths $\frac{f_{+-}}{f_{00}}=\frac{\Gamma \left(\Upsilon \right(4S)\to B^{+}{B}^{-})}{\Gamma \left(\Upsilon \right(4S)\to B^0{\overline{B}}^0)}=1.04\mathrm{}\pm 0.07\left(\mathrm{stat}\right)\pm 0.04\left(\mathrm{syst}\right)$. With the assumption that $f_{+-}{+f}_{00}=1\mathrm{}$, we obtain $f_{00}=0.49\mathrm{}\pm 0.02\left(\mathrm{stat}\right)\pm 0.01\left(\mathrm{syst}\right)$ and $f_{+-}=0.51\mathrm{}\pm 0.02\left(\mathrm{stat}\right)\pm 0.01\left(\mathrm{syst}\right)$. This production ratio and its uncertainty apply to all exclusive $B$-meson branching fractions measured at the $\Upsilon \left(4S\right)$ resonance.