Dalitz plot analyses of $B^0\to D^{-}{D}^0{K}^{+}$ and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$ decays

We present Dalitz plot analyses for the decays of $B$ mesons to $D^{-}{D}^0{K}^{+}$ and ${\overline{D}}^0{D}^0{K}^{+}$. We report the observation of the $D_{s1}^{*}(2700{)}^{+}$ resonance in these two channels and obtain measurements of the mass $M(D_{s1}^{*}(2700{)}^{+})={2699}_{-7}^{+14}\mathrm{MeV}/c^2$ and of the width $\mathrm{\Gamma }(D_{s1}^{*}(2700{)}^{+})={127}_{-19}^{+24}\mathrm{MeV}$, including statistical and systematic uncertainties. In addition, we observe an enhancement in the $D^0{K}^{+}$ invariant mass around $2350–2500\mathrm{MeV}/c^2$ in both decays $B^0\to D^{-}{D}^0{K}^{+}$ and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$, which we are not able to interpret. The results are based on $429{\mathrm{fb}}^{-1}$ of data containing $471\times 10^{6}B\overline{B}$ pairs collected at the $\mathrm{\Upsilon }(4S)$ resonance with the BABAR detector at the SLAC National Accelerator Laboratory.

Figure 1

Fits of the $m_{\mathrm{ES}}$ data distributions [15] for the modes $B^0\to D^{-}{D}^0{K}^{+}$ (top) and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$ (bottom). Points with statistical errors are data events, the red dashed line represents the signal PDF, the blue dashed line represents the background PDF, and the black solid line shows the total PDF. The vertical lines indicate the signal region used in the rest of the analysis.

Figure 2

Distributions of the data for the Dalitz plot for $B^0\to D^{-}{D}^0{K}^{+}$ (top) and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$ (bottom), where each dot represents a $B$ candidate.

Figure 3

Projections of the Dalitz plot on the $D^0{K}^{+}$ axis for the data (dots) and for the result of the preliminary fit (total histogram) for the modes $B^0\to D^{-}{D}^0{K}^{+}$ (left) and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$ (right). The fit includes the background (plain yellow histogram), the nonresonant (vertical-hatched blue histogram), the $D_{s1}^{*}(2700{)}^{+}$ (red histogram), and the $D_{s2}^{*}(2573{)}^{+}$ (plain dark gray histogram) amplitudes. For $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$, the additional charmonium contributions consist of the $\psi (3770)$ (horizontal-hatched light blue histogram) and the $\psi (4160)$ (plain light gray histogram) amplitudes.

Figure 4

Projections of the Dalitz plot on the three axes for the data (dots) and for the result of the nominal fit (total histogram) for the modes $B^0\to D^{-}{D}^0{K}^{+}$ (left) and $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$ (right). The fit includes the background (plain yellow histogram), the nonresonant (vertical-hatched blue histogram, present only for $B^0\to D^{-}{D}^0{K}^{+}$), the $D_{s1}^{*}(2700{)}^{+}$ (red histogram), the $D_{s2}^{*}(2573{)}^{+}$ (plain dark gray histogram), and the exponential (cross-hatched green histogram) amplitudes. For $B^{+}\to {\overline{D}}^0{D}^0{K}^{+}$, the additional charmonium contributions consist of the $\psi (3770)$ (horizontal-hatched light blue histogram) and the $\psi (4160)$ (plain light gray histogram) amplitudes.