We have measured the cross section of $\gamma {+D}^{*\pm }$ production in $\overline{p}p$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ using the Collider Detector at Fermilab. In this kinematic region, the Compton scattering process $(g_c\to \gamma c)$ is expected to dominate and thus provide a direct link to the charm quark density in the proton. From the $45\pm 18$ $\gamma {+D}^{*\pm }$ candidates in a $16.4{\mathrm{pb}}^{-1\mathrm{}}$ data sample, we have determined the production cross section to be $0.38\pm 0.15\left(\mathrm{stat}\right)\pm 0.11\left(\mathrm{syst}\right)$ nb for the rapidity range $|y\left(D^{*\pm }\right)|<1.2\mathrm{}$ and $|y\left(\gamma \right)|<0.9\mathrm{}$, and for the transverse momentum range $p_T\left(D^{*\pm }\right)>6\mathrm{}\mathrm{GeV}/c$ and $16<\mathrm{}{p}_T\left(\gamma \right)<40\mathrm{}\mathrm{GeV}/c$. The measured cross section is compared to a theoretical prediction.

• Received 26 June 1996

DOI:https://doi.org/10.1103/PhysRevLett.77.5005