Measurement of the Near-Threshold $e^{+}{e}^{-}\to D^{(*)\pm }{D}^{(*)\mp }$ Cross Section using Initial-State Radiation

We report a measurement of the exclusive $e^{+}{e}^{-}\to D^{(*)\pm }{D}^{*\mp }$ cross section as a function of center-of-mass energy near the $D^{(*{)}^{\pm }}{D}^{*\mp }$ threshold with initial-state radiation. A partial reconstruction technique is used to increase the efficiency and to suppress background. The analysis is based on a data sample collected with the Belle detector with an integrated luminosity of $547.8{\mathrm{fb}}^{-1}$.

Figure 1

The $M_{\mathrm{rec}}(D^{(*)+}{\gamma }_{\mathrm{isr}})$ distribution for the data: (a),(d) without requirement of slow pion; (b),(e) with $\Delta M_{\mathrm{rec}}^{\mathrm{fit}}$ requirement. Histograms show the normalized $M_{D^{(*)+}}$ sidebands contributions. (c),(f) The distribution of $\Delta M_{\mathrm{rec}}^{\mathrm{fit}}$ in the data after the refit procedure. The selected signal windows are indicated by the vertical lines.

Figure 2

The exclusive cross sections for (a) $e^{+}{e}^{-}\to D^{*+}{D}^{*-}$ and (b) $e^{+}{e}^{-}\to D^{+}{D}^{*-}$.