Rates, Polarizations, and Asymmetries in Charmless Vector-Vector $B$ Meson Decays

With a sample of approximately $89\times {10}^6$ $B\overline{B}$ pairs collected with the BABAR detector, we perform a search for $B$ meson decays into pairs of charmless vector mesons ($\phi$, $\rho$, and $K^{*}$). We measure the branching fractions, determine the degree of longitudinal polarization, and search for $CP$ violation asymmetries in the processes $B^{+}\to \phi K^{*+}$, $B^0\to \phi K^{*0}$, $B^{+}\to {\rho }^0{K}^{*+}$, and $B^{+}\to {\rho }^0{\rho }^{+}$. We also set an upper limit on the branching fraction for the decay $B^0\to {\rho }^0{\rho }^0$.

Figure 1

Projections of the multidimensional fit onto the variable $m_{\mathrm{E}\mathrm{S}}$ for (a) $B^{+}\to \phi K^{*+}$, (b) $B^0\to \phi K^{*0}$, (c) $B^{+}\to {\rho }^0{K}^{*+}$, and (d) $B^{+}\to {\rho }^0{\rho }^{+}$ candidates after a requirement on the signal-to-background probability ratio ${\mathcal{P}}_{\mathrm{s}\mathrm{i}\mathrm{g}}/{\mathcal{P}}_{\mathrm{b}\mathrm{k}\mathrm{g}}$ with the PDF for $m_{\mathrm{E}\mathrm{S}}$ excluded. The points with error bars show the data; the solid (dashed) line shows the signal-plus-background (background only) PDF projection.

Figure 2

Invariant mass projections (a) $\phi$, (b) $K^{*}$ for $B\to \phi K^{*}$; (c) ${\rho }^0$, (d) $K^{*+}$ for $B^{+}\to {\rho }^0{K}^{*+}$; (e) ${\rho }^0$, (f) ${\rho }^{+}$ for $B^{+}\to {\rho }^0{\rho }^{+}$ candidates after a requirement on the signal-to-background probability ratio ${\mathcal{P}}_{\mathrm{s}\mathrm{i}\mathrm{g}}/{\mathcal{P}}_{\mathrm{b}\mathrm{k}\mathrm{g}}$ with the PDF for mass excluded. For point and line definitions, see Fig. 1.