Evidence for the decay $B^{\pm }\to K^{*\pm }{\pi }^0$

We have measured the process $B^{\pm }\to (K^{*\pm }\to K^{\pm }{\pi }^0){\pi }^0$ with $232\times {10}^6$ ${\rm Y}(4S)\to B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. From a signal yield of $89\pm 26$ events we obtain the branching fraction $\mathcal{B}(B^{\pm }\to K^{*\pm }{\pi }^0)=[6.9\pm 2.0(\mathrm{stat})\pm 1.3(\mathrm{syst})]\times {10}^{-6}$ with a statistical significance of 3.6 standard deviations including systematic uncertainties, and a charge asymmetry of $0.04\pm 0.29(\mathrm{stat})\pm 0.05(\mathrm{syst})$.

Figure 1

Likelihood projection plots for the four fit variables, (a) $m_{\mathrm{ES}}$, (b) $\Delta E$, (c) $ANN$, and (d) $m_{K\pi }$. In each plot the solid line represents the total PDF, the dotted line represents the total background, the dotted-dashed line represents the continuum contribution, and the dashed line represents the signal component. The plots contain a subset of the events defined by a likelihood ratio of at least 0.1 (see text).