1,345 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.
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
Partial Wave Analysis of
A partial wave analysis of in
decay is presented using a sample of 14 million
events accumulated by the BES II detector. The data are fitted to
the sum of relativistic covariant tensor amplitudes for intermediate resonant
decay modes. From the fit, significant contributions to decays from
the channels , , ,
, , , and are found. Flavor-SU(3)-violating
asymmetry is observed. Values obtained for the masses and
widths of the resonances , , , and
are presented.Comment: 16 pages, 9 figures, and 4 table
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
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
Measurement of \psip Radiative Decays
Using 14 million psi(2S) events accumulated at the BESII detector, we report
first measurements of branching fractions or upper limits for psi(2S) decays
into gamma ppbar, gamma 2(pi^+pi^-), gamma K_s K^-pi^++c.c., gamma K^+ K^-
pi^+pi^-, gamma K^{*0} K^- pi^+ +c.c., gamma K^{*0}\bar K^{*0}, gamma pi^+pi^-
p pbar, gamma 2(K^+K^-), gamma 3(pi^+pi^-), and gamma 2(pi^+pi^-)K^+K^- with
the invariant mass of hadrons below 2.9GeV/c^2. We also report branching
fractions of psi(2S) decays into 2(pi^+pi^-) pi^0, omega pi^+pi^-, omega
f_2(1270), b_1^\pm pi^\mp, and pi^0 2(pi^+pi^-) K^+K^-.Comment: 5 pages, 4 figure
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
Measurement of the cross section for e^+e^- -> ppbar at center-of-mass energies from 2.0 to 3.07 GeV
Cross sections for e^+e^- -> ppbar have been measured at 10 center-of-mass
energies from 2.0 to 3.07 GeV by the BESII experiment at the BEPC, and proton
electromagnetic form factors in the time-like region have been determined.Comment: 6 pages, 3 figure
Measurements of and decays into and
Using 58 million and 14 million events collected by the
BESII detector at the BEPC, branching fractions or upper limits for the decays
and and are measured. For the isospin violating decays, the upper
limits are determined to be and at the 90% confidence level. The isospin
conserving process is observed for the
first time, and its branching fraction is measured to be , where the
first error is statistical and the second one is systematic. No signal is observed in decays, and is set at the 90%
confidence level. Branching fractions of decays into and are also reported, and the sum
of these branching fractions is determined to be .Comment: 7 pages, 10 figures. Phys.Rev.D comments considere
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