205 research outputs found
The upper limit of the e+e- partial width of X(3872)
The e+e- decay partial width of the recently observed state, X(3872), is
estimated using the ISR data collected at the center of mass energy 4.03 GeV in
e+e- annihilation experiment by BES at BEPC. It is found that the product of
the e+e- partial width and X(3872) --> pi+ pi- J/psi decay branching fraction
is less than 10 eV at 90 % confidence level if the J(PC) of X(3872) is 1(--).
Together with the potential models and other information, we conclude that
X(3872) is very unlikely to be a vector state.Comment: 5 pages, 1 figur
The interference between virtual photon and 1-- charmonium in e+e-experiment
e+e- Experiments producing charmonium are reviewed. It is found that the
contribution of the continuum amplitude via virtual photon was neglected in
almost all the experiments and the channels analyzed. It is shown that the
contribution of the continuum part may affect the final results significantly
in psi(2S) and psi(3770) decays, while the interference between continuum and
resonance amplitudes may even affect the J/psi decays as well as the psi(2S)
and psi(3770). This should be considered in analyzing the "rho-pi puzzle"
between J/psi and psi(2s) decays, and the difference between inclusive hadron
and DDbar cross sections in psi(3770) decays.Comment: 6 pages, 2 figure
The Form Factors of omega pi0 and pi+ pi- at psi(2S)
The measurements of psi(2S) -> omega pi0 and psi(2S) -> pi+ pi- in e+e-
experiments are examined. It is found that the non-resonance virtual photon
annihilation gives large contributions to the observed cross sections of these
two processes. By including this contribution, the form factors and branching
fractions of these two decay modes are revised.Comment: 6 pages, 1 figures(two diagrams), Phys. Lett. B557 (2003) 192-19
Determining the upper limit of Gamma_{ee} for the Y(4260)
By fitting the R values between 3.7 and 5.0 GeV measured by the BES
collaboration, the upper limit of the electron width of the newly discovered
resonance Y(4260) is determined to be 580 eV at 90% C.L. Together with the
BABAR measurement on the product of Gamma_{ee} and BR(Y(4260) --> pi+pi-
J/psi), this implies a large decay width of Y(4260) --> pi+pi- J/psi final
states.Comment: 8 pages, 4 figure
Measuring psi(3770) --> rho pi in e+e- experiment
In S- and D-wave mixing scheme, the branching ratio of psi(3770) --> rho pi
is estimated. Together with the continuum cross section of rho pi estimated by
form factor, the observed cross section of rho pi production at psi(3770) in
e+e- experiment is calculated taking into account the interference effect
between the resonance and continuum amplitudes and the initial state radiative
correction. The behavior of the cross section reveals that the disappearance of
rho pi signal just indicates the existence of the corresponding branching ratio
B(psi(3770) --> rho pi) at the order of 10 to the minus fourth.Comment: 6 pages, 3 figure
Baryon Antibaryon Nonets
The baryon-antibaryon SU(3) nonets are proposed as a scheme to classify the
increased number of experimentally observed enhancements near the baryon
antibaryon mass threshold. The scheme is similar to the Fermi-Yang-Sakata
model, which was put forth about fifty years ago in explaining the mesons
observed at that time. According to the present scheme, many new
baryon-antibaryon bound states are predicted, and their possible productions in
quarkonium decays and B decays are suggested for experimental search.Comment: 5 pages, 1 figur
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
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.
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
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
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