319 research outputs found
Software Engineering Strengths and Weaknesses in Systems Engineers (presentation)
Prepared for NDIA Conference, 201
Search for a dark vector gauge boson decaying to using decays
We report a search for a dark vector gauge boson that couples to
quarks in the decay chain , . No signal is found and we set a
mass-dependent limit on the baryonic fine structure constant of in the mass range of 290 to 520 MeV/. This analysis is
based on a data sample of 976 fb collected by the Belle experiment at
the KEKB asymmetric-energy collider.Comment: 6 pages, 4 figure
Invariant-mass and fractional-energy dependence of inclusive production of di-hadrons in annihilation at 10.58 GeV
The inclusive cross sections for di-hadrons of charged pions and kaons
() in electron-positron annihilation are reported. They
are obtained as a function of the total fractional energy and invariant mass
for any di-hadron combination in the same hemisphere as defined by the thrust
event-shape variable and its axis. Since same-hemisphere di-hadrons can be
assumed to originate predominantly from the same initial parton, di-hadron
fragmentation functions are probed. These di-hadron fragmentation functions are
needed as an unpolarized baseline in order to quantitatively understand related
spin-dependent measurements in other processes and to apply them to the
extraction of quark transversity distribution functions in the nucleon. The
di-hadron cross sections are obtained from a data sample
collected at or near the resonance with the Belle detector at
the KEKB asymmetric-energy collider.Comment: 21 pages, 18 figures plus 25 figures in supplemental material,
submitted to PR
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
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
Study of Excited States Decaying into and Baryons
Using a data sample of 980 of annihilation data
taken with the Belle detector operating at the KEKB asymmetric-energy
collider, we report the results of a study of excited states that
decay, via the emission of photons and/or charged pions, into or
ground state charmed-strange baryons. We present new measurements of
the masses of all members of the , ,
, , and isodoublets, measurements of
the intrinsic widths of those that decay strongly, and evidence of previously
unknown transitions.Comment: Submitted to PR
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
Measurement of branching fraction and direct asymmetry in charmless decays at Belle
We report a study of the charmless hadronic decay of the charged meson to
the three-body final state . The results are based on a data
sample that contains pairs collected at the
resonance with the Belle detector at the KEKB asymmetric-energy
collider. The measured inclusive branching fraction and the direct
asymmetry are and
, respectively, where the first uncertainties are
statistical and the second are systematic. The invariant mass
distribution of the signal candidates shows an excess in the region below
GeV/, which is consistent with the previous studies from BaBar and LHCb.
In addition, strong evidence of a large direct asymmetry is found in the
low-invariant-mass region.Comment: 7 pages, 3 figure
Evidence for a vector charmonium-like state in
We report the measurement of via
initial-state radiation using a data sample of an integrated luminosity of
921.9 fb collected with the Belle detector at the and
nearby. We find evidence for an enhancement with a 3.4 significance in
the invariant mass of The measured mass and width
are
and ,
respectively. The mass, width, and quantum numbers of this enhancement are
consistent with the charmonium-like state at 4626 MeV/ recently reported
by Belle in The product of the cross section and the branching fraction of
is measured from
threshold to 5.6 GeV.Comment: 9 pages, 4 figure
Measurement of eta_c(1S), eta_c(2S) and non-resonant eta' pi+ pi- production via two-photon collisions
We report the measurement of gamma gamma to eta_c(1S), eta_c(2S) to eta' pi+
pi- with eta' decays to gamma rho and eta pi+ pi- using 941 fb^{-1} of data
collected with the Belle detector at the KEKB asymmetric-energy e+e- collider.
The eta_c(1S) mass and width are measured to be M = [2984.6\pm0.7 (stat.)\pm2.2
(syst.)] MeV/c^{2} and \Gamma = [30.8^{+2.3}_{-2.2}~(stat.) \pm 2.5~(syst.)]
MeV, respectively. First observation of eta_c(2S) to eta' pi+ pi- with a
significance of 5.5sigma including systematic error is obtained, and the
eta_c(2S) mass is measured to be M = [3635.1\pm3.7~(stat.)\pm2.9~(syst.)]
MeV/c^{2}. The products of the two-photon decay width and branching fraction
(B) of decays to eta'pi+ pi- are determined to be \Gamma_{gamma gamma}B =
[65.4\pm2.6~(stat.)\pm6.9~(syst.)] eV for eta_c(1S) and
[5.6^{+1.2}_{-1.1}~(stat.)\pm1.1~(syst.)] eV for eta_c(2S). A new decay mode
for the eta_c(1S) to eta'f_0(2080) with f_0(2080) to pi+ pi- is observed with a
statistical significance of 20sigma. The f_0(2080) mass and width are
determined to be M = [2083^{+63}_{-66}~(stat.)\pm 32~(syst.)] MeV/c^{2} and
\Gamma = [178^{+60}_{-178}~(stat.) \pm 55~(syst.)] MeV. The cross sections for
gamma gamma to eta' pi+ pi- and eta'f_{2}(1270) are measured for the first
time.Comment: 19 pages, 14 figure
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