43 research outputs found
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays
By analyzing about 33 data sample collected at and around 3.773
GeV with the BES-II detector at the BEPC collider, we directly measure the
branching fractions for the neutral and charged inclusive semimuonic decays
to be and , and determine the ratio of the two branching
fractions to be
A study of charged kappa in
Based on events collected by BESII, the decay
is studied. In the invariant mass
spectrum recoiling against the charged , the charged
particle is found as a low mass enhancement. If a Breit-Wigner function of
constant width is used to parameterize the kappa, its pole locates at MeV/. Also in this channel,
the decay is observed for the first time.
Its branching ratio is .Comment: 14 pages, 4 figure
Study of J/Psi decays into eta Kstar Kstar-bar
We report the first observation of \mPJpsi \to \mPeta\mPKst\mAPKst decay in
a \mPJpsi sample of 58 million events collected with the BESII detector. The
branching fraction is determined to be . The selected signal event sample is further used to search for the
\mPY resonance through \mPJpsi \to \mPeta \mPY, \mPY\to\mPKst\mAPKst. No
evidence of a signal is seen. An upper limit of \mathrm{Br}(\mPJpsi \to \mPeta
\mPY)\cdot\mathrm{Br}(\mPY\to\mPKst\mAPKst) < 2.52\times 10^{-4} is set at the
90% confidence level.Comment: 11 pages, 4 figure
Measurements of the observed cross sections for e+e -> exclusive light hadrons containing K^S_0 meson at \sqrt{s} = 3.773 and 3.650 GeV
By analyzing the data sets of 17.3 pb taken at GeV
and of 6.5 pb taken at GeV with the BES-II detector at
the BEPC collider, we measure the observed cross sections for the exclusive
light hadron final states of , ,
, ,
and produced in
annihilation at the two energy points. We set the upper limits on the
observed cross sections and the branching fractions for decay to
these final states at 90% C.L..Comment: 6 pages, 1 figur
Long-range Angular Correlations On The Near And Away Side In P-pb Collisions At √snn=5.02 Tev
7191/Mar294
The impact of long-term fertilization on nitrogen leaching from double rice field of Hunan, China
Non-Peer ReviewedTo investigate the impact of long-term (1981-2007) fertilization on nitrogen leaching in soil solution of double rice field, a two years’ study was conducted in Hunan, China. Porous suction pipes was employed to extract soil solutions from different aquifers (in depth of 20-30 cm, 50-60 cm and 80-90 cm) of rice field to analyze the concentration of ammonium-N (NH4+–N) and nitrate-N (NO3––N) and the total loss of nitrogen. Results showed that nitrate-N was the primary form of N leaching in studied area. Significant seasonal variance as well vertical distribution of N leaching was found. NH4+–N in soil leachate mainly occurs in submerged situation before mid-season drainage, while NO3
––N could primarily be found in situation of saturation especially in late growing stage. Concentration of NH4+–N decreased with the increasing sampling depth in range of 0-100 cm; whereas for the NO3––N, the vertical distribution was complicated: it increased in 0-60 cm and then decreased in 60-90 cm. Long-term incorporation
with rice straw (NPKS) causes greater total N losses than applied chemical fertilizer only (NPK), and N leaching of CK (No fertilizer) was significantly less than these two treatments. For the studied area, comparatively higher N leaching losses occurred due to long-term fertilization, but with low potential hazards for nitrate contamination due to no extreme high NO3––N was found in all samples