Phys. Rev. D 95, 012001 (2017) We report the first search for the $J^{PC}=0^{--}$ glueball in $\Upsilon(1S)$
and $\Upsilon(2S)$ decays with data samples of $(102\pm2)$ million and
$(158\pm4)$ million ...events, respectively, collected with the Belle detector. No
significant signals are observed in any of the proposed production modes, and
the 90\% credibility level upper limits on their branching fractions in
$\Upsilon(1S)$ and $\Upsilon(2S)$ decays are obtained. The inclusive branching
fractions of the $\Upsilon(1S)$ and $\Upsilon(2S)$ decays into final states
with a $\chi_{c1}$ are measured to be $\BR(\Upsilon(1S)\to \chi_{c1}+ anything)
= (1.90\pm 0.43(stat.)\pm 0.14(syst.))\times 10^{-4}$ with an improved
precision over prior measurements and $\BR(\Upsilon(2S)\to \chi_{c1}+ anything)
= (2.24\pm 0.44(stat.)\pm 0.20(syst.))\times 10^{-4}$ for the first time.
We present the results of the first Dalitz plot analysis of the decay \(D^{0}\to K^{-}\pi^{+}\eta\). The analysis is performed on a data set corresponding to an integrated luminosity of 953 ...\(\rm{fb}^{-1}\) collected by the Belle detector at the asymmetric-energy \(e^{+}e^{-}\) KEKB collider. The Dalitz plot is well described by a combination of the six resonant decay channels \(\bar{K}^{*}(892)^0\eta\), \(K^{-}a_0(980)^+\), \(K^{-}a_2(1320)^+\), \(\bar{K}^{*}(1410)^0\eta\), \(K^{*}(1680)^-\pi^{+}\) and \(K_2^{*}(1980)^-\pi^{+}\), together with \(K\pi\) and \(K\eta\) S-wave components. The decays \(K^{*}(1680)^{-}\to K^{-}\eta\) and \(K_{2}^{*}(1980)^{-}\to K^{-}\eta\) are observed for the first time. We measure ratio of the branching fractions, \(\frac{\mathcal{B}(D^{0}\to K^{-}\pi^{+}\eta)}{\mathcal{B}(D^{0}\to K^{-}\pi^{+})}=0.500\pm0.002{\rm(stat)}\pm0.020{\rm(syst)}\pm0.003{\rm (\mathcal{B}_{PDG})}\). Using the Dalitz fit result, the ratio \(\frac{\mathcal{B}(K^{*}(1680)\to K\eta)}{\mathcal{B}(K^{*}(1680)\to K\pi)}\) is measured to be \(0.11\pm0.02{\rm(stat)}^{+0.06}_{-0.04}{\rm(syst)}\pm0.04{\rm(\mathcal{B}_{\text{PDG}})}\); this is much lower than the theoretical expectations (\(\approx1\)) made under the assumption that \(K^{*}(1680)\) is a pure \(1^{3}D_1\) state. The product branching fraction \(\mathcal{B}(D^0\to K_2^{*}(1980)^-\to K^{-}\eta\pi^{+})=(2.2^{+1.7}_{-1.9})\times10^{-4}\) is determined. In addition, the \(\pi\eta^{\prime}\) contribution to the \(a_0(980)^{\pm}\) resonance shape is confirmed with 10.1\(\sigma\) statistical significance using the three-channel Flatt\'{e} model. We also measure \(\mathcal{B}(D^0\to\bar{K}^{*}(892)^0\eta)=(1.41^{+0.13}_{-0.12})\%\). This is consistent with, and more precise than, the current world average \((1.02\pm0.30)\%\), deviates with a significance of more than \(3\sigma\) from the theoretical predictions of (0.51-0.92)%.
We report the measurement of \(e^+e^- \to D^+_sD^*_{s2}(2573)^-+c.c.\) via initial-state radiation using a data sample of an integrated luminosity of 921.9 fb\(^{-1}\) collected with the Belle ...detector at the \(\Upsilon(4S)\) and nearby. We find evidence for an enhancement with a 3.4\(\sigma\) significance in the invariant mass of \(D^+_sD^*_{s2}(2573)^- +c.c.\) The measured mass and width are \((4619.8^{+8.9}_{-8.0}({\rm stat.})\pm2.3({\rm syst.}))~{\rm MeV}/c^{2}\) and \((47.0^{+31.3}_{-14.8}({\rm stat.})\pm4.6({\rm syst.}))~{\rm MeV}\), respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmonium-like state at 4626 MeV/\(c^2\) recently reported by Belle in \(e^+e^-\to D^+_sD_{s1}(2536)^-+c.c.\) The product of the \(e^+e^-\to D^+_sD^*_{s2}(2573)^-+c.c.\) cross section and the branching fraction of \(D^*_{s2}(2573)^-\to{\bar D}^0K^-\) is measured from \(D^+_sD^*_{s2}(2573)^-\) threshold to 5.6 GeV.
Phys. Rev. D 94, 092006 (2016) We report a search for a dark vector gauge boson $U^\prime$ that couples to
quarks in the decay chain $D^{*+} \to D^0 \pi^+, D^0 \to K^0_S \eta, \eta \to
U^\prime ...\gamma$, $U^\prime \to \pi^+ \pi^-$. No signal is found and we set a
mass-dependent limit on the baryonic fine structure constant of $10^{-3} -
10^{-2}$ in the $U^\prime$ mass range of 290 to 520 MeV/$c^2$. This analysis is
based on a data sample of 976 fb$^{-1}$ collected by the Belle experiment at
the KEKB asymmetric-energy $e^+e^-$ collider.
Phys. Rev. D 93, 112013 (2016) The branching fractions of the $\Upsilon(1S)$ inclusive decays into final
states with a $J/\psi$ or a $\psi(2S)$ are measured with improved precision to
be ...$\BR(\Upsilon(1S)\to J/\psi + {\rm anything})=(5.25\pm
0.13(\mathrm{stat.})\pm 0.25(\mathrm{syst.}))\times 10^{-4}$ and
$\BR(\Upsilon(1S)\to \psi(2S) + {\rm anything})=(1.23\pm
0.17(\mathrm{stat.})\pm 0.11(\mathrm{syst.}))\times 10^{-4}$. The first search
for $\Upsilon(1S)$ decays into $XYZ$ states that decay into a $J/\psi$ or a
$\psi(2S)$ plus one or two charged tracks yields no significant signals for
$XYZ$ states in any of the examined decay modes, and upper limits on their
production rates in $\Upsilon(1S)$ inclusive decays are determined.
We report the discovery of $\Xi_{c}(3055)^{0}$, observed by its decay into
the final state $\Lambda D^{0}$, and present the first observation and evidence
of the decays of $\Xi_c(3055)^{+}$ and ...$\Xi_c(3080)^{+}$ into $\Lambda D^{+}$.
We also perform a combined analysis of the $\Lambda D^{+}$ with the
$\Sigma_{c}^{++}K^{-}$ and $\Sigma_{c}^{\ast ++}K^{-}$ decay modes to measure
the ratios of branching fractions, masses and widths with improved accuracy. We
measure the ratios of branching fractions ${\cal B}(\Xi_{c}(3055)^{+} \to
\Lambda D^{+})/{\cal B}(\Xi_{c}(3055)^{+} \to
\Sigma_{c}^{++}K^{-})=5.09\pm1.01\pm0.76$, ${\cal B}(\Xi_{c}(3080)^{+} \to
\Lambda D^{+})/{\cal B}(\Xi_{c}(3080)^{+} \to
\Sigma_{c}^{++}K^{-})=1.29\pm0.30\pm0.15$, and ${\cal B}(\Xi_{c}(3080)^{+} \to
\Sigma_{c}^{\ast ++}K^{-})/{\cal B}(\Xi_{c}(3080)^{+} \to
\Sigma_{c}^{++}K^{-})=1.07\pm0.27\pm0.01$, where the uncertainties are
statistical and systematic. The analysis is performed using a 980 fb$^{-1}$
data sample collected with the Belle detector at the KEKB asymmetric-energy
$e^{+}e^{-}$ collider.
Phys. Rev. D 93, 112017 (2016) The process $\gamma \gamma \to p \bar{p} K^+ K^-$ and its intermediate
processes are measured for the first time using a 980~fb$^{-1}$ data sample
collected with the ...Belle detector at the KEKB asymmetric-energy $e^+e^-$
collider. The production of $p \bar{p} K^+ K^-$ and a
$\Lambda(1520)^0~(\bar{\Lambda}(1520)^0)$ signal in the $pK^-$~($\bar{p} K^+$)
invariant mass spectrum are clearly observed. However, no evidence for an
exotic baryon near 1540~MeV/$c^2$, denoted as
$\Theta(1540)^0$~($\bar{\Theta}~(1540)^0$) or
$\Theta(1540)^{++}$~($\Theta(1540)^{--}$), is seen in the $p
K^-$~($\bar{p}K^+$) or $pK^+$~($\bar{p} K^-$) invariant mass spectra. Cross
sections for $\gamma \gamma \to p \bar{p} K^+ K^-$, $\Lambda(1520)^0 \bar{p}
K^+ +c.c.$ and the products $\sigma(\gamma \gamma \to \Theta(1540)^0 \bar{p}
K^+ +c.c.)\BR(\Theta(1540)^0 \to p K^{-})$ and $\sigma(\gamma \gamma \to
\Theta(1540)^{++} \bar{p} K^- +c.c.)\BR(\Theta(1540)^{++}\to p K^{+})$ are
measured. We also determine upper limits on the products of the $\chi_{c0}$ and
$\chi_{c2}$ two-photon decay widths and their branching fractions to $p \bar{p}
K^+ K^-$ at the 90\% credibility level.
The experimental results on the ratios of branching fractions \(\mathcal{R}(D) = {\cal B}(\bar{B} \to D \tau^- \bar{\nu}_{\tau})/{\cal B}(\bar{B} \to D \ell^- \bar{\nu}_{\ell})\) and ...\(\mathcal{R}(D^*) = {\cal B}(\bar{B} \to D^* \tau^- \bar{\nu}_{\tau})/{\cal B}(\bar{B} \to D^* \ell^- \bar{\nu}_{\ell})\), where \(\ell\) denotes an electron or a muon, show a long-standing discrepancy with the Standard Model predictions, and might hint to a violation of lepton flavor universality. We report a new simultaneous measurement of \(\mathcal{R}(D)\) and \(\mathcal{R}(D^*)\), based on a data sample containing \(772 \times 10^6\) \(B\bar{B}\) events recorded at the \(\Upsilon(4S)\) resonance with the Belle detector at the KEKB \(e^+ e^-\) collider. In this analysis the tag-side \(B\) meson is reconstructed in a semileptonic decay mode and the signal-side \(\tau\) is reconstructed in a purely leptonic decay. The measured values are \(\mathcal{R}(D)= 0.307 \pm 0.037 \pm 0.016\) and \(\mathcal{R}(D^*) = 0.283 \pm 0.018 \pm 0.014\), where the first uncertainties are statistical and the second are systematic. These results are in agreement with the Standard Model predictions within \(0.2\), \(1.1\) and \(0.8\) standard deviations for \(\mathcal{R}(D)\), \(\mathcal{R}(D^*)\) and their combination, respectively. This work constitutes the most precise measurements of \(\mathcal{R}(D)\) and \(\mathcal{R}(D^*)\) performed to date as well as the first result for \(\mathcal{R}(D)\) based on a semileptonic tagging method.
Using a data sample of \(772 \times 10^6\) BB pairs collected on the \({\Upsilon}(4S)\) resonance with the Belle detector at the KEKB asymmetric-energy \(e^+e^-\) collider, we report the observations ...of \(B^0\to p{\bar p}\pi^+\pi^-\) and \(B^+ \to p{\bar p}\pi^+\pi^0\). We measure a decay branching fraction of \((0.83 \pm 0.17 \pm 0.17) \times 10^-6\) in \(B^0\to p{\bar p}\pi^+\pi^-\) for \(M_{\pi^+\pi^-} < 1.22 GeV/c^2\) with a significance of 5.5 standard deviations. The contribution from \(B0 \to p{\bar p}K^0\) is excluded. We measure a decay branching fraction of \((4.58 \pm 1.17 \pm 0.67) \times 10^-6\) for \(B^+ \to p{\bar p}\pi^+\pi^0\) with \(M_{\pi^+\pi^0} < 1.3 GeV/c^2\) with a significance of 5.4 standard deviations. We study the difference of the \(M_{p{\bar p}}\) distributions in \(B^0\to p{\bar p}\pi^+\pi^-\) and \(B^+ \to p{\bar p}\pi^+\pi^0\).
