66 research outputs found
Observation of decays into vector meson pairs , , and
Decays of to vector meson pairs , and
are observed for the first time using
\psip events accumulated at the BESIII detector at the BEPCII
collider. The branching fractions are measured to be , , and , for , , and ,
respectively. The observation of decays into a pair of vector
mesons , and indicates that the hadron
helicity selection rule is significantly violated in decays. In
addition, the measurement of gives the rate of doubly
OZI-suppressed decay. Branching fractions for and
decays into other vector meson pairs are also measured with improved precision.Comment: 4 pages, 2 figure
First Observation of the Decays chi_{cJ} -> pi^0 pi^0 pi^0 pi^0
We present a study of the P-wave spin -triplet charmonium chi_{cJ} decays
(J=0,1,2) into pi^0 pi^0 pi^0 pi^0. The analysis is based on 106 million
\psiprime decays recorded with the BESIII detector at the BEPCII electron
positron collider. The decay into the pi^0 pi^0 pi^0 pi^0 hadronic final state
is observed for the first time. We measure the branching fractions B(chi_{c0}
-> pi^0 pi^0 pi^0 pi^0)=(3.34 +- 0.06 +- 0.44)*10^{-3}, B(chi_{c1} -> pi^0 pi^0
pi^0 pi^0)=(0.57 +- 0.03 +- 0.08)*10^{-3}, and B(chi_{c2} -> pi^0 pi^0 pi^0
pi^0)=(1.21 +- 0.05 +- 0.16)*10^{-3}, where the uncertainties are statistical
and systematical, respectively.Comment: 7 pages, 3 figure
Study of radiative decays into a vector meson
The decays () are studied with
a sample of radiative \psip\to\gamma\chi_{cJ} events in a sample of
(1.06\pm0.04)\times 10^{8} \psip events collected with the BESIII detector.
The branching fractions are determined to be: , , and . The decay is observed for the first time. Upper limits at the 90% confidence
level on the branching fractions for and \chict decays into these
final states are determined. In addition, the fractions of the transverse
polarization component of the vector meson in decays
are measured to be for , for , and for , respectively. The first errors are statistical and the second
ones are systematic.Comment: 8 pages, 3 figure
Precision measurement of the branching fractions of J/psi -> pi+pi-pi0 and psi' -> pi+pi-pi0
We study the decays of the J/psi and psi' mesons to pi+pi-pi0 using data
samples at both resonances collected with the BES III detector in 2009. We
measure the corresponding branching fractions with unprecedented precision and
provide mass spectra and Dalitz plots. The branching fraction for J/psi ->
pi+pi-pi0 is determined to be (2.137 +- 0.004 (stat.) +0.058-0.056 (syst.)
+0.027-0.026 (norm.))*10-2, and the branching fraction for psi' -> pi+pi-pi0 is
measured as (2.14 +- 0.03 (stat.) +0.08-0.07 (syst.) +0.09-0.08 (norm.))*10-4.
The J/psi decay is found to be dominated by an intermediate rho(770) state,
whereas the psi' decay is dominated by di-pion masses around 2.2 GeV/c2,
leading to strikingly different Dalitz distributions.Comment: 15 pages, 2 figure
Higher-order multipole amplitude measurement in
Using events collected with the BESIII detector at
the BEPCII storage ring, the higher-order multipole amplitudes in the radiative
transition are measured.
A fit to the production and decay angular distributions yields
and , where the first
errors are statistical and the second systematic. Here denotes the
normalized magnetic quadrupole amplitude and the normalized electric
octupole amplitude. This measurement shows evidence for the existence of the
signal with statistical significance and is consistent with
the charm quark having no anomalous magnetic moment.Comment: 14 pages, 4 figure
Measurements of h_c(^1P_1) in psi' Decays
We present measurements of the charmonium state made with 106M
events collected by BESIII at BEPCII. Clear signals are observed for
with and without the subsequent radiative decay
. First measurements of the absolute branching ratios
and
are presented. A
statistics-limited determination of the previously unmeasured width leads
to an upper limit MeV (90% confidence). Measurements of
MeV/ and are consistent with previous results.Comment: 5 pages, 1 figure, accepted for publication in Physical Review
Letter
Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/psi->gamma pi^+pi^-eta'
With a sample of (225.2\pm2.8)*10^{6} J/psi events registered in the BESIII
detector, J/psi->gamma pi^+ pi^- eta' is studied using two eta' decay modes:
eta'->pi^+ pi^- eta and eta' -> gamma rho^0. The X(1835), which was previously
observed by BESII, is confirmed with a statistical significance that is larger
than 20\sigma. In addition, in the pi^+pi^-eta' invariant mass spectrum, the
X(2120) and the X(2370), are observed with statistical significances larger
than 7.2\sigma and 6.4\sigma, respectively. For the X(1835), the angular
distribution of the radiative photon is consistent with expectations for a
pseudoscalar
Search for CP and violating pseudoscalar decays into
Using a sample of events collected with
the Beijing Spectrometer (BESIII) at the Beijing Electron-Positron Collider, CP
and violating decays of , and \etac into and
are searched for in \jpsi radiative decays. No significant
, or \etac signal is observed, and 90% confidence level upper
limits of \BR(\eta \to \pi^+\pi^-)<3.9\times 10^{-4}, \BR(\eta' \to
\pi^+\pi^-)<5.5\times 10^{-5}, \BR(\etac \to \pi^+\pi^-)<1.3\times 10^{-4},
\BR(\eta \to \pi^0 \pi^0)<6.9\times 10^{-4}, \BR(\eta' \to \pi^0
\pi^0)<4.5\times 10^{-4} and \BR(\etac \to \pi^0 \pi^0)<4.2\times 10^{-5}
are obtained.Comment: 15 pages, 6 figure
First observation of decays into
The decays and are analyzed using a sample of 225 million
\jpsi events collected with the BESIII detector. The decay of \eta(1405)\ar
f_{0}(980)\pi^0 with a large isospin violation is observed for the first time.
The width of the observed in the dipion mass spectra is
anomalously narrower than the world average. Decay rates for three-pion decays
of the are also measured precisely.Comment: Revtex, 6 pages, 4 eps figures, version accepted by Phys. Rev.
Letter
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