Observation of Diffractive $\mathit{b}$-Quark Production at the Fermilab Tevatron

We report a measurement of the fraction of $b$ quarks produced diffractively in $\overline{p}p$ collisions at $\sqrt{s}=1.8\mathrm{}$ TeV. Diffraction is identified by the absence of particles in a forward pseudorapidity region. From events with an electron of transverse momentum $9.5<\mathrm{}{p}_T^e<20\mathrm{}$ GeV/ $c$ within the pseudorapidity region $|\eta |<1.1\mathrm{}$, the ratio of diffractive to total $b$-quark production rates is found to be $R_{\overline{b}b}=[0.62\pm 0.19(\mathrm{stat})\pm 0.16(\mathrm{syst}\left)\right]\%$. This result is comparable in magnitude to corresponding ratios for $W$ and dijet production but significantly lower than expectations based on factorization.