Measurement of Branching Fraction and Search for $CP$ Violation in $B\to \varphi \varphi K$

Abstract

We report the measurement of branching fractions and $CP$-violation asymmetries in $B\to \varphi \varphi K$ decays based on a $711{\mathrm{fb}}^{-1}$ data sample containing $772\times 10^6$ $B\bar{B}$ events. The data were recorded at the ${\rm Y}(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. For $B^{+}\to \varphi \varphi K^{+}$, the branching fraction and $CP$-violation asymmetry measured below the ${\eta }_c$ threshold ($m_{\varphi \varphi }<2.85\mathrm{GeV}/c^2$) are $[3.43_{-0.46}^{+0.48}(\mathrm{stat})\pm 0.22(\mathrm{syst})]\times 10^{-6}$ and $-0.02\pm 0.11(\mathrm{stat})\pm 0.01(\mathrm{syst})$, respectively. Similarly, the branching fraction obtained for $B^0\to \varphi \varphi K^0$ below the ${\eta }_c$ threshold is $[3.02_{-0.66}^{+0.75}(\mathrm{stat})\pm 0.20(\mathrm{syst})]\times 10^{-6}$. We also measure the $CP$-violation asymmetry for $B^{+}\to \varphi \varphi K^{+}$ within the ${\eta }_c$ region ($m_{\varphi \varphi }\in [2.94,3.02]\mathrm{GeV}/c^2$) to be $+0.12\pm 0.12(\mathrm{stat})\pm 0.01(\mathrm{syst})$.

Comments: 8 pages, 6 figures, 4 tables, submitted to Phys. Rev. D