326 research outputs found
On the mechanisms of heavy-quarkonium hadroproduction
We discuss the various mechanisms potentially at work in hadroproduction of
heavy quarkonia in the light of computations of higher-order QCD corrections
both in the Colour-Singlet (CS) and Colour-Octet (CO) channels and the
inclusion of the contribution arising from the s-channel cut in the CS channel.
We also discuss new observables meant to better discriminate between these
different mechanisms.Comment: Invited review talk at 3rd International Conference On Hard And
Electromagnetic Probes Of High-Energy Nuclear Collisions (HP2008), 8-14 June
2008, Illa da Toxa, Galicia, Spain. 11 pages, 21 figures, LaTeX, uses
svjour.cls and svepj.clo (included
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Search for the Lepton Flavor Violation Processes and
The lepton flavor violation processes and are
searched for using a sample of 5.8 events collected with
the BESII detector. Zero and one candidate events, consistent with the
estimated background, are observed in and
decays, respectively. Upper limits on the branching ratios are determined to be
and at the 90% confidence level (C.L.).Comment: 9 pages, 2 figure
The pole in
Using a sample of 58 million events recorded in the BESII detector,
the decay is studied. There are conspicuous
and signals. At low mass, a large
broad peak due to the is observed, and its pole position is determined
to be - MeV from the mean of six analyses.
The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL
Measurements of the Mass and Full-Width of the Meson
In a sample of 58 million events collected with the BES II detector,
the process J/ is observed in five different decay
channels: , , (with ), (with
) and . From a combined fit of all five
channels, we determine the mass and full-width of to be
MeV/ and
MeV/.Comment: 9 pages, 2 figures and 4 table. Submitted to Phys. Lett.
Observation of the decay \psip\rar\kstark
Using 14 million events collected with the BESII detector,
branching fractions of \psip\rar\kstarkpm and \kstarknn are determined to
be: \calB(\psip\rar\kstarkpm)=(2.9^{+1.3}_{-1.7}\pm0.4)\times 10^{-5} and
\calB(\psip\rar\kstarknn)=(13.3^{+2.4}_{-2.7}\pm1.9)\times 10^{-5}. The
results confirm the violation of the "12%" rule for these two decay channels
with higher precision. A large isospin violation between the charged and
neutral modes is observed.Comment: 5 pages, 3 figure
Recommended from our members
Measurement of Bottom versus Charm as a Function of Transverse Momentum with Electron-Hadron Correlations in p+p Collisions at sqrt(s)=200 GeV
The momentum distribution of electrons from semi-leptonic decays of charm and
bottom for mid-rapidity |y|<0.35 in p+p collisions at sqrt(s)=200 GeV is
measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC)
over the transverse momentum range 2 < p_T < 7 GeV/c. The ratio of the yield of
electrons from bottom to that from charm is presented. The ratio is determined
using partial D/D^bar --> e^{+/-} K^{-/+} X (K unidentified) reconstruction. It
is found that the yield of electrons from bottom becomes significant above 4
GeV/c in p_T. A fixed-order-plus-next-to-leading-log (FONLL) perturbative
quantum chromodynamics (pQCD) calculation agrees with the data within the
theoretical and experimental uncertainties. The extracted total bottom
production cross section at this energy is \sigma_{b\b^bar}= 3.2
^{+1.2}_{-1.1}(stat) ^{+1.4}_{-1.3}(syst) micro b.Comment: 432 authors, 6 pages text, 3 figures. Submitted to Phys. Rev. Lett.
Plain text data tables for the points plotted in figures for this and
previous PHENIX publications are (or will be) publicly available at
http://www.phenix.bnl.gov/papers.htm
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
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