4 research outputs found
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
Dalitz plot analysis of the decay
Using a low-background sample of
events, about 5 times larger statistics than previous experiments, we present a
Dalitz plot analysis of the decay . It
is found that the Dalitz plot distribution differs from the pure -wave phase
space with a statistical significance of . The parameters from the
fit to data are in reasonable agreement with those without the cross-channel
effect within the dispersive framework, which indicates that the cross-channel
effect in is not significant.Comment: 9 pages, 9 figure
Search for Baryon and Lepton Number Violation in
Using events collected by the BESIII detector at the Beijing Electron Positron Collider, we search for the process for the first time. In this process, both baryon and lepton number conservation is violated. No signal is found and the upper limit on the branching fraction is set to be at the 90\% Confidence Level
Study of two-photon decays of pseudoscalar mesons via J/Psi radiative decays
Using a sample of 4.48 x 10(8) Psi(3686) events collected with the BESIII detector at the BEPCII collider, we study the two-photon decays of the pseudoscalar mesons pi(0,) eta , eta' , eta(1405), eta(1475), eta(1760), and X(1835) in J/Psi radiative decays using Psi(3686) -> pi(+) pi(-) J/Psi events. The pi(0), eta, and eta' mesons are clearly observed in the two-photon mass spectra, and the branching fractions are determined to be B(J/Psi -> gamma pi(0) -> 3 gamma) = (3.57 +/- 0.12 +/- 0.16) x 10(-5), B(J/Psi -> gamma eta -> 3 gamma) = (4.42 +/- 0.04 +/- 0.18) x 10(-4), and B(J/Psi -> gamma eta' -> 2 gamma) = (1.26 +/- 0.02 +/- 0.05) x 10(-4), where the first error is statistical and the second is systematic. No clear signal for eta(1405), eta(1475), eta(1760) or X(1835) is observed in the two- photon mass spectra, and upper limits at the 90% confidence level on the product branching fractions are obtained