Search for prompt production of ${\chi }_c$ and $X(3872)$ in $e^{+}{e}^{-}$ annihilations

We have searched for prompt production of ${\chi }_{c1}$, ${\chi }_{c2}$ and $X(3872)$ in continuum $e^{+}{e}^{-}$ annihilations using a $386{\mathrm{fb}}^{-1}$ data sample collected around $\sqrt{s}=10.6\mathrm{GeV}$ with the BABAR detector using the $\gamma J/\psi$ decay mode. After accounting for the feed-down from $\psi (2S)\to \gamma {\chi }_{c1,2}$, no significant signal for prompt ${\chi }_{c1,2}$ production is observed. We present improved upper limits at 90% confidence level on the production cross sections of 77 fb for ${\chi }_{c1}$ and 79 fb for ${\chi }_{c2}$, for events where the ${\chi }_c$ momentum exceeds 2.0 GeV and there are at least three additional charged tracks. These limits are consistent with NRQCD predictions. We also set an upper limit on the prompt production of $X(3872)$ through the decay $X(3872)\to \gamma J/\psi$.

Figure 1

Nominal fit result for the ${\chi }_c$ search (left) and the $X(3872)$ search (right) from the $386{\mathrm{fb}}^{-1}$ data sample ($p^{*}>2.0\mathrm{GeV}$). The points represent the data, the dashed lines are background PDFs, the solid lines below the points are signal PDFs, and the solid lines on the points are the total PDFs.