Observation of B --> eta' K* and Evidence for B --> eta' rho+

Abstract

We present an observation of $B\to {\eta }^{\prime }{K}^{\ast }$. The data sample corresponds to 232 million $B\bar{B}$ pairs collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We measure the branching fractions (in units of $10^{-6}$) $\mathcal{B}(B^0\to {\eta }^{\prime }{K}^{\ast 0})=3.8\pm 1.1\pm 0.5$ and $\mathcal{B}(B^{+}\to {\eta }^{\prime }{K}^{\ast +})=4.9_{-1.7}^{+1.9}\pm 0.8$, where the first error is statistical and the second systematic. A simultaneous fit results in the observation of $B\to {\eta }^{\prime }{K}^{\ast }$ with $\mathcal{B}(B\to {\eta }^{\prime }{K}^{\ast })=4.1_{-0.9}^{+1.0}\pm 0.5$. We also search for $B\to {\eta }^{\prime }\rho$ and $B\to {\eta }^{\prime }{f}_0(980)(f_0\to {\pi }^{+}{\pi }^{-})$ with results and 90% confidence level upper limits $\mathcal{B}(B^{+}\to {\eta }^{\prime }{\rho }^{+})=8.7_{-2.8}^{+3.1}{}_{-1.3}^{+2.3}$ ($<14$), $\mathcal{B}(B^0\to {\eta }^{\prime }{\rho }^0)<3.7$ and $\mathcal{B}(B^0\to {\eta }^{\prime }{f}_0(980)(f_0\to {\pi }^{+}{\pi }^{-}))<1.5$. Charge asymmetries in the channels with significant yields are consistent with zero.

7 pages, 2 figures, version published in Phys. Rev. Lett