The cross section for $b\overline{b}$ production in $800\mathrm{GeV}/c$ $\mathrm{pN}$ interactions has been measured in Fermilab experiment E771 to be ${43}_{-17\mathrm{}}^{+27\mathrm{}}\left(\mathrm{stat}{)}_{-7\mathrm{}}^{+7\mathrm{}}\right(\mathrm{syst})\mathrm{nb}$ per nucleon from the observation of events in which both the $b$ and the $\overline{b}$ decay semimuonically or a $B$ decays into a $J/\psi$ followed by $J/\psi \to {\mu }^{+}{\mu }^{-}$.

• Received 7 July 1997

DOI:https://doi.org/10.1103/PhysRevLett.82.41