Measurement of Branching Fractions and Charge Asymmetries in B+ --> rho+pi0 and B+ -->rho0pi+ Decays, and Search for B0 --> rho0pi0

Abstract

We present measurements of branching fractions and charge asymmetries in $B$-meson decays to ${\rho }^{+}{\pi }^0$, ${\rho }^0{\pi }^{+}$ and ${\rho }^0{\pi }^0$. The data sample comprises $89\times 10^6$ ${\rm Y}(4S)\to B\bar{B}$ decays collected with the $BaBar$ detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We find the charge-averaged branching fractions $\mathcal{B}(B^{+}\to {\rho }^{+}{\pi }^0)=(10.9\pm 1.9(\mathrm{stat})\pm 1.9(\mathrm{syst}))\times 10^{-6}$ and $\mathcal{B}(B^{+}\to {\rho }^0{\pi }^{+})=(9.5\pm 1.1(\mathrm{stat})\pm 0.8(\mathrm{syst}))\times 10^{-6}$, and we set a 90% confidence-level upper limit $\mathcal{B}(B^0\to {\rho }^0{\pi }^0)<2.9\times 10^{-6}$. We measure the charge asymmetries $A_{CP}^{{\rho }^{+}{\pi }^0}=0.24\pm 0.16\pm 0.06$ and $A_{CP}^{{\rho }^0{\pi }^{+}}=-0.19\pm 0.11\pm 0.02$.

7 pages, 1 figure, Submitted to Phys. Rev. Lett