Measurement of $\gamma +b+X$ and $\gamma +c+X$ Production Cross Sections in $p\overline{p}$ Collisions at $\sqrt{s}=1.96\mathrm{TeV}$

First measurements of the differential cross sections $d^3\sigma /(d{p}_T^{\gamma }d{y}^{\gamma }d{y}^{\mathrm{jet}})$ for the inclusive production of a photon in association with a heavy quark ($b$, $c$) jet are presented, covering photon transverse momenta $30<p_T^{\gamma }<150\mathrm{GeV}$, photon rapidities $|y^{\gamma }|<1.0$, jet rapidities $|y^{\mathrm{jet}}|<0.8$, and jet transverse momenta $p_T^{\mathrm{jet}}>15\mathrm{GeV}$. The results are based on an integrated luminosity of $1{\mathrm{fb}}^{-1}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.96\mathrm{TeV}$ recorded with the D0 detector at the Fermilab Tevatron Collider. The results are compared with next-to-leading order perturbative QCD predictions.

Figure 1

Distribution of observed events for $P_{\mathrm{HF}-\mathrm{jet}}$ after all selection criteria for the bin $50<p_T^{\gamma }<70\mathrm{GeV}$. The distributions for the $b$, $c$, and light jet templates are shown normalized to their fitted fraction. Error bars on the templates represent combined uncertainties from statistics of the MC and the fitted jet flavor fractions, while the data contain just statistical uncertainties. Fits in the other $p_T^{\gamma }$ bins are of similar quality.

Figure 2

The $\gamma +b+X$ and $\gamma +c+X$ differential cross sections as a function of $p_T^{\gamma }$ in the two regions $y^{\gamma }{y}^{\mathrm{jet}}>0$ and $y^{\gamma }{y}^{\mathrm{jet}}<0$. The uncertainties on the data points include statistical and systematic contributions added in quadrature. The NLO pQCD predictions using cteq6.6M PDFs are indicated by the dotted lines.

Figure 3

The data-to-theory ratio of cross sections as a function of $p_T^{\gamma }$ for $\gamma +b+X$ and $\gamma +c+X$ in the regions $y^{\gamma }{y}^{\mathrm{jet}}>0$ and $y^{\gamma }{y}^{\mathrm{jet}}<0$. The uncertainties on the data include both statistical (inner line) and full uncertainties (entire error bar). Also shown are the uncertainties on the theoretical pQCD scales and the cteq6.6M PDFs. The scale uncertainties are shown as dotted lines and the PDF uncertainties by the shaded regions. The ratio of the standard cteq6.6M prediction to two models of intrinsic charm is also shown.