Evidence for $B_s^0\to \varphi \varphi$ Decay and Measurements of Branching Ratio and $A_{CP}$ for $B^{+}\to \varphi K^{+}$

We present the first evidence of charmless decays of the $B_s^0$ meson, the decay $B_s^0\to \varphi \varphi$, and a measurement of the branching ratio $\mathrm{BR}(B_s^0\to \varphi \varphi )$ using $180{\mathrm{pb}}^{-1}$ of data collected by the CDF II experiment at the Fermilab Tevatron collider. In addition, the BR and direct $CP$ asymmetry for the $B^{+}\to \varphi K^{+}$ decay are measured. We obtain $\mathrm{BR}(B_s^0\to \varphi \varphi )=[{14}_{-5}^{+6}(\mathrm{stat})\pm 6(\mathrm{syst})]\times {10}^{-6}$, $\mathrm{BR}(B^{+}\to \varphi K^{+})=[7.6\pm 1.3(\mathrm{stat})\pm 0.6(\mathrm{syst})]\times {10}^{-6}$, and $A_{CP}(B^{+}\to \varphi K^{+})=-0.07\pm 0.17(\mathrm{stat})\genfrac{}{}{0ex}{}{+0.03}{-0.02}(\mathrm{syst})$. Both decays are governed in the standard model by second order (penguin) $b\to s\overline{s}s$ amplitudes.

Figure 1

$m_{KKK}$ (left) and $m_{KK}$ (right) distributions for $B^{+}\to \varphi K^{+}$ with projections of the total likelihood function and its components. $B^{+}\to K^{+}{K}^{-}{K}^{+}$ is the sum of nonresonant and $B^{+}\to f_0(980)K^{+}$ contributions, while $B^{+}\to K^{+}{\pi }^{-}{\pi }^{+}$ includes nonresonant and $B^{+}\to K^{*0}(892){\pi }^{+}$.

Figure 2

Invariant mass distribution for $B_s^0\to \varphi \varphi$ (left) and $B_s^0\to J/\psi \varphi$ (right) candidates. The arrows indicate the signal region for the $B_s^0\to \varphi \varphi$ search. The fit described in the text is superimposed on the $m_{\mu \mu KK}$ distribution.