Phys. Rev. D 91, 032008 (2015) We report a measurement of the $B^0$ and $B^+$ meson decays to the
$D_s^-K^0_S \pi^+$ and $D_s^- K^+K^+$ final states, respectively, using $657
\times 10^{6} ...B\overline{B}$ pairs collected at the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Using
the $D_s^-\to \phi\pi^-$, $K^{*}(892)^0 K^-$ and $K^0_S K^-$ decay modes for
the $D_s$ reconstruction, we measure the following branching fractions: ${\cal
B}(B^0\to D_s^{-}K^0_S\pi^+)=0.47 \pm 0.06 (\mathrm {stat}) \pm 0.05 (\mathrm
{syst})\times 10^{-4}$ and ${\cal B}(B^+\to D_s^-K^+K^+)= 0.93 \pm 0.22
(\mathrm {stat})\pm 0.10 (\mathrm {syst})\times 10^{-5}$. We find the ratio of
the branching fraction of $B^+\to D_s^-K^+K^+$ to that of the analogous Cabibbo
favored $B^+\to D_s^-K^+\pi^+$ decay to be ${\cal R}_{\cal B} = 0.054 \pm 0.013
({\rm stat}) \pm 0.006 ({\rm syst})$, which is consistent with the na\"{\i}ve
factorization model. We also observe a deviation from the three-body
phase-space model for both studied decays.
Phys. Rev. D 90, 112008 (2014) Using data samples of $102\times10^6$ $\Upsilon(1S)$ and $158\times10^6$
$\Upsilon(2S)$ events collected with the Belle detector, a first experimental
search has been ...made for double-charmonium production in the exclusive decays
$\Upsilon(1S,2S)\rightarrow J/\psi(\psi')+X$, where $X=\eta_c$, $\chi_{cJ}
(J=~0,~1,~2)$, $\eta_c(2S)$, $X(3940)$, and $X(4160)$. No significant signal is
observed in the spectra of the mass recoiling against the reconstructed
$J/\psi$ or $\psi'$ except for the evidence of $\chi_{c1}$ production with a
significance of $4.6\sigma$ for $\Upsilon(1S)\rightarrow J/\psi+\chi_{c1}$. The
measured branching fraction $\BR(\Upsilon(1S)\rightarrow J/\psi+\chi_{c1})$ is
$(3.90\pm1.21(\rm stat.)\pm0.23 (\rm syst.))\times10^{-6}$. The $90\%$
confidence level upper limits on the branching fractions of the other modes
having a significance of less than $3\sigma$ are determined. These results are
consistent with theoretical calculations using the nonrelativistic QCD
factorization approach.
Phys. Rev. D 91, 051101(R) We report the first observation of $B^0 \to X(3872) (K^{+}\pi^{-})$ and
evidence for $B^+ \to X(3872) (K^{0}\pi^{+})$. We measure the product of
branching fractions for the ...former to be ${\cal B}(B^0 \to X(3872) (K^+ \pi^-))
\times {\cal B}(X(3872) \to J/\psi \pi^+ \pi^-) = (7.9 \pm 1.3(\mbox{stat.})\pm
0.4(\mbox{syst.})) \times 10^{-6}$ and find that $B^{0}\to X(3872)
K^{*}(892)^{0}$ does not dominate the $B^{0}\to X(3872)K^{+}\pi^{-}$ decay
mode. We also measure ${\cal B}(B^+ \to X(3872) (K^0 \pi^+)) \times {\cal
B}(X(3872) \to J/\psi \pi^+ \pi^-) = (10.6 \pm 3.0(\mbox{stat.}) \pm
0.9(\mbox{syst.})) \times 10^{-6}$. This study is based on the full data sample
of 711~fb$^{-1}$ ($772\times 10^6 B\bar B$ pairs) collected at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB collider.
Here, we report a measurement of D0- D ¯ 0 mixing parameters and a search for indirect CP violation through a time-dependent amplitude analysis of D0 → KS0π+π- decays. The results are based on 921 ...fb-1 of data accumulated with the Belle detector at the KEKB asymmetric-energy e+e- collider. Assuming CP conservation, we measure the mixing parameters x= ( 0.56±0.19-0.09-0.09+0.03+0.06 ) % and y= ( 0.30± 0.15-0.05-0.06+0.04+0.03 ) % , where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. Lastly, with CP violation allowed, the parameters | q / p | =0.90-0.15-0.04-0.05+0.16+0.05+0.06 and arg ( q / p ) = ( -6±11±3-4+3 ) ° are found to be consistent with conservation of CP symmetry in mixing and in the interference between mixing and decay, respectively.
Phys. Rev. D 93, 011101 (2016) We report new measurements of the total cross sections for $e^+e^-\to
\Upsilon(n{\rm S})\pi^+\pi^-$ ($n$ = 1, 2, 3) and $e^+e^-\to b\bar b$ from a
high-luminosity fine ...scan of the region $\sqrt{s} = 10.63$-$11.05$ GeV with the
Belle detector. We observe that the $\Upsilon(n{\rm S})\pi^+\pi^-$ spectra have
little or no non-resonant component and extract from them the masses and widths
of $\Upsilon(10860)$ and $\Upsilon(11020)$ and their relative phase. We find
$M_{10860}=(10891.1\pm3.2^{+0.6}_{-1.7})$ MeV/$c^2$ and
$\Gamma_{10860}=(53.7^{+7.1}_{-5.6}\,^{+1.3}_{-5.4})$ MeV and report first
measurements $M_{11020}=(10987.5^{+6.4}_{-2.5}\,^{+9.0}_{-2.1})$ MeV/$c^2$,
$\Gamma_{11020}=(61^{+9}_{-19}\,^{+2}_{-20})$ MeV, and $\phi_{\rm
11020}-\phi_{\rm 10860} = (-1.0\pm0.4\,^{+1.4}_{-0.1})$ rad.
We report the first observation of the \(\Xi_{c}(2930)^0\) charmed-strange baryon with a significance greater than 5\(\sigma\). The \(\Xi_{c}(2930)^0\) is found in its decay to \(K^- \Lambda_{c}^+\) ...in \(B^{-} \to K^{-} \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}\) decays. The measured mass and width are \(2928.9 \pm 3.0(\rm stat.)^{+0.9}_{-12.0}(\rm syst.)\) MeV/\(c^{2}\) and \(19.5 \pm 8.4(\rm stat.) ^{+5.9}_{-7.9}(\rm syst.)\) MeV, respectively, and the product branching fraction is \({\cal B}(B^{-} \to \Xi_{c}(2930)^0 \bar{\Lambda}_{c}^{-}) {\cal B}(\Xi_{c}(2930)^0 \to K^- \Lambda_{c}^{+})=1.73 \pm 0.45(\rm stat.) \pm 0.21(\rm syst.)\times 10^{-4}\). We also measure \({\cal B}(B^{-} \to K^{-} \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-}) = 4.80 \pm 0.43(\rm stat.) \pm 0.60(\rm syst.) \times 10^{-4}\) with improved precision, and search for the charmonium-like state \(Y(4660)\) and its spin partner, \(Y_{\eta}\), in the \(\Lambda_{c}^{+}\bar{\Lambda}_{c}^{-}\) invariant mass spectrum. No clear signals of the \(Y(4660)\) nor its spin partner are observed and the 90\% credibility level (C.L.) upper limits on their production rates are determined. These measurements are obtained from a sample of \((772\pm11)\times 10^{6} B\bar{B}\) pairs collected at the \(\Upsilon(4S)\) resonance by the Belle detector at the KEKB asymmetric energy electron-positron collider.
Phys. Rev. D 90, 072009 (2014) We report a search for charmless hadronic decays of neutral $B$ mesons to
$\eta' K^{*}(892)^{0}$. The results are based on a 711fb$^{-1}$ data sample
that contains ...$772\times 10^6 B\overline{B}$ pairs, collected at the
$\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric energy
$e^+e^-$ collider. We observe the decay for the first time with a significance
of 5.0 standard deviations and obtain its branching fraction ${\cal
B}B^0\to\eta' K^{*}(892)^{0}=2.6\pm0.7{\rm (stat)}\pm0.2{\rm (syst)}\times
10^{-6}$. We also measure the $CP$ violating asymmetry as ${\cal
A}_{CP}B^0\to\eta' K^{*}(892)^{0}=-0.22\pm0.29{\rm (stat)}\pm0.07{\rm syst}$.
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