191 research outputs found
An amplitude analysis of the system produced in radiative decays
An amplitude analysis of the system produced in radiative
decays is presented. In particular, a piecewise function that
describes the dynamics of the system is determined as a
function of from an analysis of the
decays collected by the BESIII detector.
The goal of this analysis is to provide a description of the scalar and tensor
components of the system while making minimal assumptions about
the properties or number of poles in the amplitude. Such a model-independent
description allows one to integrate these results with other related results
from complementary reactions in the development of phenomenological models,
which can then be used to directly fit experimental data to obtain parameters
of interest. The branching fraction of is
determined to be , where the uncertainty is
systematic only and the statistical uncertainty is negligible.Comment: Submitted to Phys. Rev. D 19 pages, 4 figure
Measurement of the proton form factor by studying
Using data samples collected with the BESIII detector at the BEPCII collider,
we measure the Born cross section of at 12
center-of-mass energies from 2232.4 to 3671.0 MeV. The corresponding effective
electromagnetic form factor of the proton is deduced under the assumption that
the electric and magnetic form factors are equal . In
addition, the ratio of electric to magnetic form factors, , and
are extracted by fitting the polar angle distribution of the proton
for the data samples with larger statistics, namely at 2232.4 and
2400.0 MeV and a combined sample at = 3050.0, 3060.0 and 3080.0 MeV,
respectively. The measured cross sections are in agreement with recent results
from BaBar, improving the overall uncertainty by about 30\%. The
ratios are close to unity and consistent with BaBar results in
the same region, which indicates the data are consistent with the
assumption that within uncertainties.Comment: 13 pages, 24 figure
Measurement of the branching fractions of and in
We study decays to final states involving the with a
482pb data sample collected at = 4.009GeV with the
\mbox{BESIII} detector at the BEPCII collider. We measure the branching
fractions = (8.81.80.5)
and = ()
where the first uncertainty is statistical and the second is systematic. In
addition, we estimate an upper limit on the non-resonant branching ratio
at the 90
confidence level. Our results are consistent with CLEO's recent measurements
and help to resolve the disagreement between the theoretical prediction and
CLEO's previous measurement of
Measurement of the leptonic decay width of using initial state radiation
Using a data set of 2.93 fb taken at a center-of-mass energy of
= 3.773 GeV with the BESIII detector at the BEPCII collider, we
measure the process and determine the product of the branching fraction and the
electronic width ~eV. Using the earlier-published BESIII result for
= (5.973 0.007 0.037)\%, we derive the electronic width ~= (5.58
0.05 0.08) keV.Comment: 8 pages, 2 figure
Measurement of the cross section and search for at center-of-mass energies between 3.810 and 4.600~GeV
Using data samples collected with the BESIII detector operating at the BEPCII
collider at center-of-mass energies from 3.810 to 4.600 GeV, we perform a study
of and . Statistically significant
signals of are observed at = 4.190,
4.210, 4.220, 4.230, 4.245, 4.260, 4.360 and 4.420 GeV, while no signals of
are observed. The measured energy-dependent
Born cross section for shows an enhancement around
4.2~GeV. The measurement is compatible with an earlier measurement by Belle,
but with a significantly improved precision
Observation of the isospin-violating decay
Using a sample of 1.31 billion events collected with the BESIII
detector at the BEPCII collider, the decays and are
investigated. The isospin violating decay
with , is observed for the first time. The width of the
obtained from the dipion mass spectrum is found to be much smaller
than the world average value. In the mass spectrum, there
is evidence of production. By studying the decay , the branching fractions of and
, as well as their ratio, are also measured.Comment: 10 pages, 10 figures, published in Phys. Rev.
Measurement of the Matrix Elements for the Decays and
Based on a sample of events collected with the
BESIII detector at the BEPCII collider, Dalitz plot analyses of selected 79,625
events, 33,908
events and 1,888
events are performed. The measured
matrix elements of are in reasonable agreement
with previous measurements. The Dalitz plot slope parameters of
and
are determined to be and , respectively, where the first uncertainties are statistical and the
second systematic. Both values are consistent with previous measurements, while
the precision of the latter one is improved by a factor of three. Final state
interactions are found to have an important role in those decays.Comment: 12 pages, 7 figure
Observation of the state in at BESIII
We report the observation of the in the process with a statistical
significance of , in data samples at center-of-mass energies
4.230, 4.260, 4.360, 4.420 and 4.600~GeV collected with the BESIII
detector at the BEPCII electron positron collider. The measured mass of the
is ~MeV/, where the first error is
statistical and the second systematic, and the width is less than ~MeV at
the 90\% confidence level. The products of the Born cross sections for
and the branching ratio are also measured. These measurements are in good
agreement with the assignment of the as the charmonium
state.Comment: 7 pages, 3 figures, version to appear in Phys. Rev. Let
Search for the isospin violating decay
Using data samples collected at center of mass energies of =
4.009, 4.226, 4.257, 4.358, 4.416 and 4.599 GeV with the BESIII detector
operating at the BEPCII storage ring, we search for the isospin violating decay
. No signal is observed, and upper
limits on the cross section
at the 90\% confidence level are determined to be 3.6, 1.7, 2.4, 1.4, 0.9 and
1.9 pb, respectively.Comment: 7 pages, 2 figure
Observation of the Dalitz Decay
We report the first observation of the Dalitz decay , based on a data sample of 1.31 billion events collected with
the BESIII detector. The mesons are produced via the decay process. The ratio is measured to be
. This
corresponds to a branching fraction . The transition form
factor is extracted and different expressions are compared to the measured
dependence on the invariant mass. The results are consistent with the
prediction of the Vector Meson Dominance model.Comment: 11 pages,7 figure
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