683 research outputs found
Towards φ3/γ extraction in a study of D∗ρ at Belle
We report on progress in an angular time-dependent analysis of the B0 → D∗∓ρ± decay at the Belle experiment. The study aims to establish a novel method for studying CP violation using this decay by measuring 2φ1 + φ3 (2β + γ) of the Unitarity Triangle
Search for decays to invisible final states at Belle
We report the result from the first search for decays to invisible
final states. The analysis is performed on a data sample of 924
collected at and near the and resonances with the
Belle detector at the KEKB asymmetric-energy collider. The
absolute branching fraction is determined using an inclusive sample,
obtained by fully reconstructing the rest of the particle system including the
other charmed particle. No significant signal yield is observed and an upper
limit of is set on the branching fraction of to
invisible final states at 90\% confidence level.Comment: 17 pages, 4 figures, submitted to PRD(RC
Energy scan of the cross sections and evidence for decays into charged bottomonium-like states
Using data collected with the Belle detector at the KEKB asymmetric-energy
collider, we measure the energy dependence of the cross sections from thresholds up to GeV.
We find clear and peaks with little or no
continuum contribution. We study the resonant substructure of the
transitions and find evidence that they
proceed entirely via the intermediate isovector states and
. The relative fraction of these states is loosely constrained by
the current data: the hypothesis that only is produced is excluded
at the level of 3.3 standard deviations, while the hypothesis that only
is produced is not excluded at a significant level.Comment: 8 pages, 4 figures, submitted to Physical Review Letter
Study of e+e- => B(*) B(*)-bar pi+- at sqrt(s)=10.866 GeV
We report the analysis of the three-body e+e- => B B-bar pi, B B*-bar pi, and
B* B*-bar pi processes, including the first observation of the Zb+-(10610) =>[B
B*-bar+c.c.]+- and Zb+-(10650) => [B*B*-bar]+- transitions. We measure visible
cross sections for the three-body production of sigma_vis(e+e- => [B
B*-bar+c.c.]+-pi-+=(11.2+-1.0(stat.)+-1.2(syst.)) pb and sigma_vis(e+e- =>
[B*B*-bar]+-pi-+)=(5.61+-0.73(stat.)+-0.66(syst.)) pb and set a 90% C.L. upper
limit of sigma_vis(e+e- => [BB-bar]+-pi-+)<2.1 pb. The results are based on a
121.4 1/fb data sample collected with the Belle detector at a center-of-mass
energy near the Y(5S) peak.Comment: 8 pages, 2 figure
Measurements of the masses and widths of the and baryons
We present measurements of the masses and decay widths of the baryonic states
and using a data sample
corresponding to an integrated luminosity of 711 fb collected with the
Belle detector at the KEKB asymmetric-energy collider operating at
the resonance. We report the mass differences with respect to
the baryon MeV/, MeV/,
MeV/, MeV/, and the decay widths
MeV/,
MeV/,
MeV/,
MeV/,
where the first uncertainties are statistical and the second are systematic.
The isospin mass splittings are measured to be
MeV/ and
MeV/. These results are the most precise to date.Comment: 13 pages, 4 figures, Submitted to PRD(RC
Observation of an alternative candidate in
We perform a full amplitude analysis of the process , where refers to either or . A new
charmoniumlike state that decays to is observed with a
significance of . Its mass is ()
MeV/ and width is () MeV. The
hypothesis is favored over the hypothesis at the level
of . The analysis is based on the 980 data sample
collected by the Belle detector at the asymmetric-energy collider
KEKB.Comment: 17 pages, 11 figure
Measurement of the CKM Matrix Element from at Belle
We present a new measurement of the CKM matrix element from decays, reconstructed with the full Belle data set
of integrated luminosity. Two form factor
parameterizations, originally conceived by the Caprini-Lellouch-Neubert (CLN)
and the Boyd, Grinstein and Lebed (BGL) groups, are used to extract the product
and the decay form factors, where
is the normalization factor and is a small
electroweak correction. In the CLN parameterization we find
, , , . For the BGL parameterization we
obtain , which is consistent with the World Average when correcting for
. The branching fraction of is measured to be . We also present a new
test of lepton flavor universality violation in semileptonic decays,
. The errors correspond to the statistical and
systematic uncertainties respectively. This is the most precise measurement of
and form factors to date and the first
experimental study of the BGL form factor parameterization in an experimental
measurement
Observation of
We report the first observation of the decays . The data sample of fb used in this analysis corresponds
to million pairs, collected at the resonance by
the Belle detector at the KEKB asymmetric-energy collider. We
observe and excesses of events for the two decay
modes and measure the branching fractions of and to be
and ,
respectively, where the first uncertainties are statistical and the second are
systematic. These results are not compatible with the predictions based on the
generalized factorization approach. In addition, a threshold enhancement in the
di-baryon () system is observed, consistent with that observed
in similar decays.Comment: 16 pages, 3 figures and 3 tables, submitted to PR
Inclusive cross sections for pairs of identified light charged hadrons and for single protons in at 10.58 GeV
We report the first double differential cross sections of two charged pions
and kaons () in electron-positron annihilation as a
function of the fractional energies of the two hadrons for any charge and
hadron combination. The dependence of these di-hadron cross sections on the
topology (same, opposite-hemisphere or anywhere) is also studied with the help
of the event shape variable thrust and its axis. The ratios of these di-hadron
cross sections for different charges and hadron combinations directly shed
light on the contributing fragmentation functions. For example, we find that
the ratio of same-sign pion pairs over opposite-sign pion pairs drops toward
higher fractional energies where disfavored fragmentation is expected to be
suppressed. These di-hadron results are obtained from a
data sample collected near the resonance with the Belle detector
at the KEKB asymmetric-energy collider. Extending the previously
published single-pion and single-kaon cross sections, single-proton () cross sections are extracted from a data
sub-sample.Comment: submitted to PR
Observation of and search for violation in radiative charm decays
We report the first observation of the radiative charm decay and the first search for violation in decays , , and , using a data sample of
943 fb collected with the Belle detector at the KEKB asymmetric-energy
collider. The branching fraction is measured to be , where the first
uncertainty is statistical and the second is systematic. The obtained
asymmetries, , , and
, are consistent with no violation. We also present an improved
measurement of the branching fractions and
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