1,564 research outputs found
Measurement of the branching fractions of psi(2S) -> 3(pi+pi-) and J/psi -> 2(pi+pi-)
Using data samples collected at sqrt(s) = 3.686GeV and 3.650GeV by the BESII
detector at the BEPC, the branching fraction of psi(2S) -> 3(pi+pi-) is
measured to be [4.83 +- 0.38(stat) +- 0.69(syst)] x 10^-4, and the relative
branching fraction of J/psi -> 2(pi+pi-) to that of J/psi -> mu+mu- is measured
to be [5.86 +- 0.19(stat) +- 0.39(syst)]% via psi(2S) -> (pi+pi-)J/psi, J/psi
-> 2(pi+pi-). The electromagnetic form factor of 3(pi+pi-) is determined to be
0.21 +- 0.02 and 0.20 +- 0.01 at sqrt(s) = 3.686GeV and 3.650GeV, respectively.Comment: 17pages, 7 figures, submitted to Phys. Rev.
Measurement of the chi_{c2} Polarization in psi(2S) to gamma chi_{c2}
The polarization of the chi_{c2} produced in psi(2S) decays into gamma
chi_{c2} is measured using a sample of 14*10^6 psi(2S) events collected by
BESII at the BEPC. A fit to the chi_{c2} production and decay angular
distributions in psi(2S) to gamma chi_{c2}, chi_{c2} to pi pi and KK yields
values x=A_1/A_0=2.08+/-0.44 and y=A_2/A_0=3.03 +/-0.66, with a correlation
rho=0.92 between them, where A_{0,1,2} are the chi_{c2} helicity amplitudes.
The measurement agrees with a pure E1 transition, and M2 and E3 contributions
do not differ significantly from zero.Comment: 6 pages, 4 figures, 1 tabl
Measurements of J/psi decays into phi pi^0, phi eta, and phi eta^prime
Based on 5.8x10^7 J/psi events detected in BESII, the branching fractions of
J/psi--> phi eta and phi eta^prime are measured for different eta and eta^prime
decay modes. The results are significantly higher than previous measurements.
An upper limit on B(J/psi--> phi pi^0) is also obtained.Comment: 9 pages, 10 figure
Observation of p pbar pi^0 and p pbar eta in psi' decays
The processes psi'-->p pbar pi^0 and psi'-->p pbar eta are studied using a
sample of 14 million psi' decays collected with the Beijing Spectrometer at the
Beijing Electron-Positron Collider. The branching fraction of psi'-->p pbar
pi^0 is measured with improved precision as (13.2\pm 1.0\pm 1.5)\times 10^{-5},
and psi'-->p pbar eta is observed for the first time with a branching fraction
of (5.8\pm 1.1\pm 0.7)\times 10^{-5}, where the first errors are statistical
and the second ones are systematic.Comment: 15 pages, 8 figures and 3 table
Measurements of decays into Vector- Tensor final states
Decays of the into vector plus tensor meson final states have been
studied with 14 million events collected with the BESII detector.
Branching fractions of \psi(2S) \rt \omega f_{2}(1270), ,
and are
determined. They improve upon previous BESI results and confirm the violation
of the "12%" rule for decays to VT channels with higher precision.Comment: 7 pages, 7 figures and 2 table
Measurement of the final states , , and from \psip electromagnetic decays and \ee annihilations
Cross sections and form factors for \ee \to \wpi, , and
\rho\etap at center of mass energies of 3.650, 3.686, and 3.773 GeV are
measured using data samples collected with the BESII detector at the BEPC.
Also, the branching fractions of \psi(2S) \rar \wpi, , and
\rho\etap are determined to be ,
, and
, respectively.Comment: 8 pages, 4 figures, 4 table
First Measurement of the Branching Ratio of
Using 58 million events taken with the BES II detector at the
Beijing Electron Positron Collider, a new decay mode is observed for the
first time. The branching ratio is determined to be , where the quoted
errors are statistical and systematic, respectively.Comment: 7 pages, 3 figure
\psi(2S) Decays into \J plus Two Photons
Using \gamma \gamma J/\psi, J/\psi \ra e^+ e^- and events
from a sample of \psip decays collected with the BESII
detector, the branching fractions for \psip\ra \pi^0\J, \eta\J, and
\psi(2S)\ar\gamma\chi_{c1},\gamma\chi_{c2}\ar\gamma\gamma\jpsi are measured
to be B(\psip\ra \pi^0\J) = (1.43\pm0.14\pm0.13)\times 10^{-3}, B(\psip\ra
\eta\J) = (2.98\pm0.09\pm0.23)%,
B(\psi(2S)\ar\gamma\chi_{c1}\ar\gamma\gamma\jpsi) = (2.81\pm0.05\pm 0.23)%,
and B(\psi(2S)\ar\gamma\chi_{c2}\ar\gamma\gamma\jpsi) = (1.62\pm0.04\pm
0.12)%.Comment: 7 pages, 6 figures. submitted to Phys. Rev.
Experimental study of decays to \K^+ K^- \pi^+ \pi^- \pi^0 final states
final states are studied using a sample of
decays collected with the Beijing Spectrometer
(BESII) at the Beijing Electron-Position Collider. The branching fractions of
decays to , , , , , and are determined. The first two agree with previous
measurements, and the last five are first measurements.Comment: 19 pages, 9 figure
First observation of
Using 14 million events collected with the Beijing Spectrometer
(BESII) at the Beijing Electron-Positron Collider, the branching fractions of
decays to and and the branching
fractions of the main background channels ,
, , and are determined. The contributions of the
resonances in are also
discussed.Comment: 19 pages, 8 figures, add vertex requirement systematic erro
- …