Measurement of branching fraction and final-state asymmetry for the ${\overline{B}}^0\to K_S^0{K}^{\mp }{\pi }^{\pm }$ decay

We report a measurement of the branching fraction and final-state asymmetry for the ${\overline{B}}^0\to K_S^0{K}^{\mp }{\pi }^{\pm }$ decays. The analysis is based on a data sample of $711{\mathrm{fb}}^{-1}$ collected at the $\mathrm{\Upsilon }(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We obtain a branching fraction of $(3.60\pm 0.33\pm 0.15)\times {10}^{-6}$ and a final-state asymmetry of $(-8.5\pm 8.9\pm 0.2)\%$, where the first uncertainties are statistical and the second are systematic. Hints of peaking structures are found in the differential branching fractions measured as functions of Dalitz variables.

Figure 1

Signal-enhanced projections of the fit to ${\overline{B}}^0\to K_S^0{K}^{\mp }{\pi }^{\pm }$ decays on $\mathrm{\Delta }E$, $M_{\mathrm{bc}}$, and $C_{\mathrm{NN}}^{\prime }$. (a) $\mathrm{\Delta }E$ in $5.272\mathrm{GeV}/c^2<M_{\mathrm{bc}}<5.288\mathrm{GeV}/c^2$ and $0<C_{\mathrm{NN}}^{\prime }<5$. (b) $M_{\mathrm{bc}}$ in $|\mathrm{\Delta }E|<0.05\mathrm{GeV}$ and $0<C_{\mathrm{NN}}^{\prime }<5$. (c) $C_{\mathrm{NN}}^{\prime }$ in $|\mathrm{\Delta }E|<0.05\mathrm{GeV}$ and $5.272\mathrm{GeV}/c^2<M_{\mathrm{bc}}<5.288\mathrm{GeV}/c^2$.

Figure 2

Background-subtracted Dalitz plot of the ${\overline{B}}^0\to K_S^0{K}^{\mp }{\pi }^{\pm }$ decays.

Figure 3

Differential branching fraction as functions of Dalitz variables.

Figure 4

Differential branching fraction as functions of the Dalitz variables for the two reconstructed $B$ final states: $K_S^0{K}^{-}{\pi }^{+}$ (red points with error bars) and $K_S^0{K}^{+}{\pi }^{-}$ (blue points with error bars).