Limit on Bottom-Meson Pair Production inπ−-Nucleus Interactions at 225 GeV/c

In an experiment to measure multimuon final states in interactions of 225-GeV/c ${\pi }^{-}$ with nuclear targets we have observed 65 900 $\frac{J}{\psi }\to {\mu }^{+}{\mu }^{-}$ decays, of which 487 are accompanied by a third muon. We have used this sample to search for production of bottommeson pairs, followed by the decays $B\to \frac{J}{\psi }+X$, $\overline{B}\to \mu +X$. We find, supposing linear $A$ dependence, that $\sigma \left(B\overline{B}\right)<\mathrm{}8\mathrm{}$ nb/nucleon with 90% confidence. This limit is in contradiction with a recent report that $\sigma \left(B\overline{B}\right)\approx 200$ nb/nucleon.