Phys. Rev. D 101, 052012 (2020) 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 $B^+ \to
p{\bar p}\pi^+\pi^0$.
MILAGRO (Megacity Initiative: Local And Global Research Observations) is an international collaborative project to examine the behavior and the export of atmospheric emissions from a megacity. The ...Mexico City Metropolitan Area (MCMA) - one of the world's largest megacities and North America's most populous city - was selected as the case study to characterize the sources, concentrations, transport, and transformation processes of the gases and fine particles emitted to the MCMA atmosphere and to evaluate the regional and global impacts of these emissions. The findings of this study are relevant to the evolution and impacts of pollution from many other megacities. The measurement phase consisted of a month-long series of carefully coordinated observations of the chemistry and physics of the atmosphere in and near Mexico City during March 2006, using a wide range of instruments at ground sites, on aircraft and satellites, and enlisting over 450 scientists from 150 institutions in 30 countries. Three ground supersites were set up to examine the evolution of the primary emitted gases and fine particles. Additional platforms in or near Mexico City included mobile vans containing scientific laboratories and mobile and stationary upward-looking lidars. Seven instrumented research aircraft provided information about the atmosphere over a large region and at various altitudes. Satellite-based instruments peered down into the atmosphere, providing even larger geographical coverage. The overall campaign was complemented by meteorological forecasting and numerical simulations, satellite observations and surface networks. Together, these research observations have provided the most comprehensive characterization of the MCMA's urban and regional atmospheric composition and chemistry that will take years to analyze and evaluate fully. In this paper we review over 120 papers resulting from the MILAGRO/INTEX-B Campaign that have been published or submitted, as well as relevant papers from the earlier MCMA-2003 Campaign, with the aim of providing a road map for the scientific community interested in understanding the emissions from a megacity such as the MCMA and their impacts on air quality and climate. This paper describes the measurements performed during MILAGRO and the results obtained on MCMA's atmospheric meteorology and dynamics, emissions of gases and fine particles, sources and concentrations of volatile organic compounds, urban and regional photochemistry, ambient particulate matter, aerosol radiative properties, urban plume characterization, and health studies. A summary of key findings from the field study is presented.
Phys. Rev. D 99, 071102 (2019) We report the results of a search for the $B \to Y(4260) K, ~Y(4260)\to
J/\psi\pi^+\pi^-$ decays. This study is based on a data sample corresponding to
an integrated ...luminosity of 711~fb$^{-1}$, collected at the $\Upsilon(4S)$
resonance with the Belle detector at the KEKB asymmetric-energy $e^+ e^-$
collider. We investigate the $J/\psi\pi^+\pi^-$ invariant mass distribution in
the range 4.0 to 4.6 GeV/$c^2$ using both $B^+ \to J/\psi \pi^+\pi^- K^+$ and
$B^0 \to J/\psi \pi^+\pi^- K^0_S$ decays. We find excesses of events above the
background levels, with a significances of 2.1 and 0.9 standard deviations for
charged and neutral $B \to Y(4260) K$ decays, respectively, taking into account
the systematic uncertainties. These correspond to upper limits on the product
of branching fractions, ${\cal B}(B^+ \to Y(4260) K^+) \times {\cal B}(Y(4260)
\to J/\psi \pi^+ \pi^-) <1.4 \times 10^{-5}$ and ${\cal B}(B^0 \to Y(4260) K^0)
\times {\cal B}(Y(4260) \to J/\psi \pi^+ \pi^-) <1.7 \times 10^{-5}$ at the
90\% confidence level.
Phys. Rev. Lett. 124, 122001 (2020) We report the first observation of the radiative decay of the $\Upsilon(1S)$
into a charmonium state. The statistical significance of the observed signal of
...$\Upsilon(1S) \to \gamma \chi_{c1}$ is 6.3 standard deviations including
systematics. The branching fraction is calculated to be Br($\Upsilon(1S) \to
\gamma \chi_{c1}$) = (4.7^{+2.4}_{-1.8} (stat) ^{+0.4}_{-0.5} (sys)) * 10^{-5}.
We also searched for $\Upsilon(1S)$ radiative decays into $\chi_{c0,2}$ and
$\eta_c(1S,2S)$ and set upper limits on their branching fractions. These
results are obtained from a 24.9 fb^{-1} data sample collected with the Belle
detector at the KEKB asymmetric-energy $e^+e^-$ collider at a center-of-mass
energy equal to the $\Upsilon(2S)$ mass using $\Upsilon(1S)$ tagging by the
$\Upsilon(2S) \to \Upsilon(1S) \pi^+\pi^-$ transitions.
Phys. Rev. D 101, 032007 (2020) We report the result for a search for the leptonic decay of $B^+ \to \mu^+ \,
\nu_{\mu}$ using the full Belle data set of 711 fb^{-1}$ of integrated
luminosity at the ...$\Upsilon(4S)$ resonance. In the Standard Model leptonic
$B$-meson decays are helicity and CKM suppressed. To maximize sensitivity an
inclusive tagging approach is used to reconstruct the second $B$ meson produced
in the collision. The directional information from this second $B$ meson is
used to boost the observed $\mu$ into the signal $B$ meson rest-frame, in which
the $\mu$ has a monochromatic momentum spectrum. Though its momentum is smeared
by the experimental resolution, this technique improves the analysis
sensitivity considerably. Analyzing the $\mu$ momentum spectrum in this frame
we find $\mathcal{B}(B^+ \to \mu^+ \, \nu_\mu) = \left( 5.3 \pm 2.0 \pm 0.9
\right) \times 10^{-7}$ with a one-sided significance of 2.8 standard
deviations over the background-only hypothesis. This translates to a
frequentist upper limit of $\mathcal{B}(B^+ \to \mu^+ \, \nu_{\mu}) < 8.6
\times 10^{-7}$ at 90% CL. The experimental spectrum is then used to search for
a massive sterile neutrino, $B^+ \to \mu^+ \, N$, but no evidence is observed
for a sterile neutrino with a mass in a range of 0 - 1.5 GeV. The determined
$B^+ \to \mu^+ \, \nu_{\mu}$ branching fraction limit is further used to
constrain the mass and coupling space of the type II and type III
two-Higgs-doublet models.
We report a new measurement of the $e^+e^-\to\Upsilon(nS)\pi^+\pi^-$
($n=1,2,3$) cross sections at energies from 10.52 to 11.02 GeV using data
collected with the Belle detector at the KEKB ...asymmetric-energy $e^+e^-$
collider. We observe a new structure in the energy dependence of the cross
sections; if described by a Breit-Wigner function its mass and width are found
to be $M=(10752.7\pm5.9\,^{+0.7}_{-1.1})\,$MeV/$c^2$ and
$\Gamma=(35.5^{+17.6}_{-11.3}\,^{+3.9}_{-3.3})\,$MeV, where the first error is
statistical and the second is systematic. The global significance of the new
structure including systematic uncertainty is 5.2 standard deviations. We also
find evidence for the $e^+e^-\to\Upsilon(1S)\pi^+\pi^-$ process at the energy
10.52 GeV, which is below the $B\bar{B}$ threshold.
Phys. Rev. D 98, 112016 (2018) We present the result of the search for the rare $B$ meson decay of $B^+ \to
\ell^{\,+} \nu_{\ell} \gamma$ with $\ell =e,\mu$. For the search the full data
set recorded ...by the Belle experiment of $711 \, \mathrm{fb}^{-1}$ integrated
luminosity near the $\Upsilon (4S)$ resonance is used. Signal candidates are
reconstructed for photon energies $E_{\gamma}$ larger than $1 \, \mathrm{GeV}$
using a novel multivariate tagging algorithm. The novel algorithm fully
reconstructs the second $B$ meson produced in the collision using hadronic
modes and was specifically trained to recognize the signal signature in
combination with hadronic tag-side $B$ meson decays. This approach greatly
enhances the performance. Background processes that can mimic this signature,
mainly charmless semileptonic decays and continuum processes, are suppressed
using multivariate methods. The number of signal candidates is determined by
analyzing the missing mass squared distribution as inferred from the signal
side particles and the kinematic properties of the tag-side $B$ meson. No
significant excess over the background-only hypothesis is observed and upper
limits on the partial branching fraction $ \Delta \mathcal{B} $ with
$E_{\gamma}> 1 \, \mathrm{GeV}$ individually for electron and muon final states
as well as for the average branching fraction of both lepton final states are
reported. We find a Bayesian upper limit of $\Delta \mathcal{B}( B^{+} \to
\ell^{\, +} \nu_{\ell} \gamma) < 3.0 \times 10^{-6}$ at 90% CL and also report
an upper limit on the first inverse moment of the light-cone distribution
amplitude of the $B$ meson of $\lambda_B$ at 90% CL.
Phys. Rev. D 100, 011101 (2019) We report a measurement of the branching fraction and final-state asymmetry
for the $\bar{B}^{0}\to K^{0}_{S}K^{\mp}\pi^{\pm}$ decays. The analysis is
based on a data ...sample of 711 $\rm{fb}^{-1}$ collected at the $\Upsilon(4S)$
resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$
collider. We obtain a branching fraction of $(3.60\pm0.33\pm0.15)\times10^{-6}$
and a final-state asymmetry of $(-8.5\pm8.9\pm0.2)\%$, where the first
uncertainties are statistical and the second are systematic. Hints of peaking
structures are seen in the differential branching fractions measured as
functions of Dalitz variables.
Phys. Rev. D 102, 012003 (2020) We report searches for $B^0\to\rm{invisible}$ and
$B^0\to\rm{invisible}+\gamma$ decays, where the energy of the photon is
required to be larger than 0.5 GeV. These ...results are obtained from a
$711\,{\rm fb}^{-1}$ data sample that contains $772 \times 10^6 B\bar{B}$ pairs
and was collected near the $\Upsilon\,(4S)$ resonance with the Belle detector
at the KEKB $e^+ e^-$ collider. We observe no significant signal for either
decay and set upper limits on their branching fractions at $90\%$ confidence
level of $\mathcal{B}\,(B^0\to\rm{invisible}) < 7.8\times10^{-5}$ and
$\mathcal{B}\,(B^0\to\rm{invisible}+\gamma) < 1.6\times10^{-5}$.
Phys. Rev. D 100, 031101 (2019) We present the first measurements of the absolute branching fractions of
$\Xi_c^+$ decays into $\Xi^- \pi^+ \pi^+$ and $p K^- \pi^+$ final states. Our
analysis is ...based on a data set of $(772\pm 11)\times 10^{6}$ $B\bar{B}$ pairs
collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB
$e^+e^-$ collider. We measure the absolute branching fraction of $\bar{B}^{0}
\to \bar{\Lambda}_{c}^{-} \Xi_{c}^{+}$ with the $\Xi_c^+$ recoiling against
$\bar{\Lambda}_c^-$ in $\bar{B}^0$ decays resulting in ${\cal B}(\bar{B}^{0}
\to \bar{\Lambda}_{c}^{-} \Xi_{c}^{+}) = 1.16 \pm 0.42(\rm stat.) \pm 0.15(\rm
syst.) \times 10^{-3}$. We then measure the product branching fractions ${\cal
B}(\bar{B}^{0} \to \bar{\Lambda}_c^- \Xi_c^+){\cal B}(\Xi_c^+ \to \Xi^- \pi^+
\pi^+)$ and ${\cal B}(\bar{B}^{0} \to \bar{\Lambda}_c^- \Xi_c^+){\cal
B}(\Xi_c^+ \to p K^- \pi^+)$. Dividing these product branching fractions by
$\bar{B}^{0} \to \bar{\Lambda}_{c}^{-} \Xi_{c}^{+}$ yields: ${\cal B}(\Xi_c^+
\to \Xi^- \pi^+ \pi^+) = 2.86 \pm 1.21(\rm stat.) \pm 0.38(\rm syst.)\%$ and
${\cal B}(\Xi_c^+ \to p K^- \pi^+)=0.45 \pm 0.21(\rm stat.) \pm 0.07(\rm
syst.)\%$. Our result for ${\cal B}(\Xi_c^+ \to \Xi^- \pi^+ \pi^+)$ can be
combined with $\Xi_c^+$ branching fractions measured relative to $\Xi_c^+ \to
\Xi^- \pi^+ \pi^+$ to set the absolute scale for many $\Xi_c^+$ branching
fractions.
PDF