We present a measurement of the average multiplicity of $\phi$ mesons in $B^0$, $\kern 0.18em\bar{ \kern -0.18em B}{ }^0$ and $B^\pm$ meson decays. Using $17.6 fb^{ -1}$ of data taken at the $\Upsilon{ (4S)}\xspace$ resonance by the { \slshape B\kern-0.1em{ \smaller A}\kern-0.1em B\kern-0.1em{ \smaller A\kern-0.2em R}} detector at the PEP-II $e^+e^-\xspace$ storage ring at the Stanford Linear Accelerator Center, we reconstruct $\phi$ mesons in the $K^+K^-$ decay mode and measure ${ \cal{ B}}(B\to \phi X) = (3.41\pm0.06\pm0.12)%$. This is significantly more precise than any previous measurement.
Categories: hep-ex