Rare $B$ Decays into States Containing a $J/\psi$ Meson and a Meson with $s\overline{s}$ Quark Content

We report a study of the $B$ meson decays, $B^{+}\to J/\psi \varphi K^{+}$, $B^0\to J/\psi \varphi K_S^0$, $B^0\to J/\psi \varphi$, $B^0\to J/\psi \eta$, and $B^0\to J/\psi {\eta }^{\prime }$ using $56\times {10}^6$ $B\overline{B}$ events collected at the ${\rm Y}(4S)$ resonance with the BABAR detector at the PEP-II $e^{+}{e}^{-}$ asymmetric-energy storage ring. We measure the branching fractions $\mathcal{B}(B^{+}\to J/\psi \varphi K^{+})=\mathbf{(}4.4\pm 1.4(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 0.5(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mathbf{)}\times {10}^{-5}$ and $\mathcal{B}(B^0\to J/\psi \varphi K_S^0)=\mathbf{(}5.1\pm 1.9(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\pm 0.5(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\mathbf{)}\times {10}^{-5}$, and set upper limits at $90\%$ confidence level for the branching fractions $\mathcal{B}(B^0\to J/\psi \varphi )<9.2\times {10}^{-6}$, $\mathcal{B}(B^0\to J/\psi \eta )<2.7\times {10}^{-5}$, and $\mathcal{B}(B^0\to J/\psi {\eta }^{\prime })<6.3\times {10}^{-5}$.

Figure 1

Quark diagrams: (a) Tree diagram for $B\to J/\psi \pi$ and $J/\psi \rho$, (b) rescattering for $B\to J/\psi \varphi$, (c) strange sea quarks, and (d) gluon coupling for $B\to J/\psi \varphi K$.

Figure 2

The $B^{+}\to J/\psi \varphi K^{+}$ mode. The $\Delta E$ vs $m_{\mathrm{E}\mathrm{S}}$ event distribution is shown in (a) with a small rectangle corresponding to the signal region selection defined in Table 2. The $\Delta E$ projection with a $m_{\mathrm{E}\mathrm{S}}$ signal region selection is shown in (b). The $m_{\mathrm{E}\mathrm{S}}$ projection with a $\Delta E$ signal region selection is shown in (c). The solid line in (c) is the fit described in the text. The Gaussian component includes both the signal and peaking background.

Figure 3

The $B^0\to J/\psi \varphi K_S^0$ mode. The descriptions of (a), (b), and (c) follow those of Figs. 2, respectively.