Measurement of charmless $B$ Decays to $\eta K^*$ and $\eta \rho$

Abstract

We report branching fractions and CP asymmetries for $B \to \eta K^*$ and $B \to \eta \rho$ decays. These results are obtained from a $414 {\rm fb}^{-1}$ data sample collected at the $\Upsilon(4S)$ resonance, with the Belle detector at the KEKB asymmetric energy $e^+ e^-$ collider. The branching fractions, in parts per million, of $\eta K^{*0}$, $\eta K^{*+}$, $\eta \rho^0$, and $\eta \rho^+$ are $15.9\pm 1.2 \pm 0.9$, $19.7^{+2.0}_{-1.9} \pm 1.4$, $0.84^{+0.56}_{-0.51} \pm 0.18$, and $4.1^{+1.4}_{-1.3} \pm 0.34$, respectively. We find no evidence for CP asymmetries in these modes.