572 research outputs found
Observation and study of the decay
We report the observation and study of the decay
using events
collected with the BESIII detector. Its branching fraction, including all
possible intermediate states, is measured to be
. We also report evidence for a structure,
denoted as , in the mass spectrum in the GeV/
region. Using two decay modes of the meson ( and
), a simultaneous fit to the mass spectra is
performed. Assuming the quantum numbers of the to be , its
significance is found to be 4.4, with a mass and width of MeV/ and MeV, respectively, and a
product branching fraction
. Alternatively, assuming , the
significance is 3.8, with a mass and width of MeV/ and MeV, respectively, and a product
branching fraction
. The angular distribution of
is studied and the two assumptions of the
cannot be clearly distinguished due to the limited statistics. In all
measurements the first uncertainties are statistical and the second systematic.Comment: 10 pages, 6 figures and 4 table
Observation of in
Using a sample of events recorded with
the BESIII detector at the symmetric electron positron collider BEPCII, we
report the observation of the decay of the charmonium state
into a pair of mesons in the process
. The branching fraction is measured for the first
time to be , where the first uncertainty is
statistical, the second systematic and the third is from the uncertainty of
. The mass and width of the are
determined as MeV/ and
MeV.Comment: 13 pages, 6 figure
Observation of and confirmation of its large branching fraction
The baryonic decay is observed, and the
corresponding branching fraction is measured to be
, where the first uncertainty is statistical
and second systematic. The data sample used in this analysis was collected with
the BESIII detector operating at the BEPCII double-ring collider with
a center-of-mass energy of 4.178~GeV and an integrated luminosity of
3.19~fb. The result confirms the previous measurement by the CLEO
Collaboration and is of greatly improved precision, which may deepen our
understanding of the dynamical enhancement of the W-annihilation topology in
the charmed meson decays
First observations of hadrons
Based on events collected with
the BESIII detector, five hadronic decays are searched for via process
. Three of them, ,
, and are observed for the first
time, with statistical significances of 7.4, , and
9.1, and branching fractions of ,
, and ,
respectively, where the first uncertainties are statistical and the second
systematic. No significant signal is observed for the other two decay modes,
and the corresponding upper limits of the branching fractions are determined to
be and at 90% confidence level.Comment: 17 pages, 16 figure
Measurements of Weak Decay Asymmetries of , , , and
Using production from a 567 pb
data sample collected by BESIII at 4.6 GeV, a full angular analysis is carried
out simultaneously on the four decay modes of , , , and . For the first time, the
transverse polarization is studied in unpolarized
collisions, where a non-zero effect is observed with a statistical significance
of 2.1. The decay asymmetry parameters of the weak
hadronic decays into , , and
are measured to be ,
,
, and
, respectively. In comparison with
previous results, the measurements for the and
modes are consistent but with improved precision, while the parameters for the
and modes are measured for the first time
Observation of and Improved Measurements of
Using a data sample corresponding to an integrated luminosity of
2.93~fb recorded by the BESIII detector at a center-of-mass energy of
GeV, we present an analysis of the decays and . By performing a partial wave
analysis, the -wave contribution to
is observed to be % with a statistical significance greater
than 10, besides the dominant -wave contribution. This is the first
observation of the -wave contribution. We measure the branching fractions
, , and . An upper limit
of is set at the 90% confidence level. We also obtain the hadronic
form factor ratios of at assuming the
single-pole dominance parameterization:
,
Evidence for the decays of and
We study the hadronic decays of to the final states
and , using an annihilation
data sample of 567 pb taken at a center-of-mass energy of 4.6 GeV with
the BESIII detector at the BEPCII collider. We find evidence for the decays
and with
statistical significance of and , respectively.
Normalizing to the reference decays and
, we obtain the ratios of the branching fractions
and to be and , respectively. The upper limits at the 90\% confidence level are
set to be and . Using BESIII measurements of the
branching fractions of the reference decays, we determine
() and
(). Here, the first uncertainties are statistical and the second
systematic. The obtained branching fraction of is
consistent with the previous measurement, and the branching fraction of
is measured for the first
time.Comment: Accepted by Chin. Phys. C : Chin. Phys. C 43, 083002, (2019
Early M-Protein Dynamics Predicts Progression-Free Survival in Patients With Relapsed/Refractory Multiple Myeloma
This study aimed to predict long-term progression-free survival (PFS) using early M-protein dynamic measurements in patients with relapsed/refractory multiple myeloma (MM). The PFS was modeled based on dynamic M-protein data from two phase III studies, POLLUX and CASTOR, which included 569 and 498 patients with relapsed/refractory MM, respectively. Both studies compared active controls (lenalidomide and dexamethasone, and bortezomib and dexamethasone, respectively) alone vs. in combination with daratumumab. Three M-protein dynamic features from the longitudinal M-protein data were evaluated up to different time cutoffs (1, 2, 3, and 6 months). The abilities of early M-protein dynamic measurements to predict the PFS were evaluated using Cox proportional hazards survival models. Both univariate and multivariable analyses suggest that maximum reduction of M-protein (i.e., depth of response) was the most predictive of PFS. Despite the statistical significance, the baseline covariates provided very limited predictive value regarding the treatment effect of daratumumab. However, M-protein dynamic features obtained within the first 2 months reasonably predicted PFS and the associated treatment effect of daratumumab. Specifically, the areas under the time-varying receiver operating characteristic curves for the model with the first 2 months of M-protein dynamic data were ~ 0.8 and 0.85 for POLLUX and CASTOR, respectively. Early M-protein data within the first 2 months can provide a prospective and reasonable prediction of future long-term clinical benefit for patients with MM
Search for heavy Majorana neutrino in lepton number violating decays of D→Kπe+e+
Using a data sample with an integrated luminosity of 2.93 fb-1 taken at the center-of-mass energy of 3.773 GeV, we search for the Majorana neutrino (νm) in the lepton number violating decays D→Kπe+e+. No significant signal is observed, and the upper limits on the branching fraction at the 90% confidence level are set to be B(D0→K-π-e+e+)<2.8×10-6, B(D+→KS0π-e+e+)<3.3×10-6 and B(D+→K-π0e+e+)<8.5×10-6. The Majorana neutrino is searched for with different mass assumptions ranging from 0.25 to 1.0 GeV/c2 in the decays D0→K-e+νm,νm→π-e+ and D+→KS0e+νm,νm→π-e+, and the upper limits on the branching fraction at the 90% confidence level are at the level of 10-7∼10-6, depending on the mass of the Majorana neutrino. The constraints on the mixing matrix element |Veνm|2 are also evaluated
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