Search results for "BESIII Detector"

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Observation of e(+)e(-) -> gamma X(3872) at BESIII

2014

With data samples collected with the BESIII detector operating at the BEPCII storage ring at center-of-mass energies from 4.009 to 4.420 GeV, the process e(+)e(-) -> gamma X(3872) is observed for the first time with a statistical significance of 6.3 sigma. The measured mass of the X(3872) is (3871.9 +/- 0.7(stat) +/- 0.2(syst)) MeV/c(2), in agreement with previous measurements. Measurements of the product of the cross section sigma[e(+)e(-) -> gamma X(3872)] and the branching fraction B [X(3872) -> pi(+)pi(-)J/psi] at center-of-mass energies 4.009, 4.229, 4.260, and 4.360 GeV are reported. Our measurements are consistent with expectations for the radiative transition process Y(4260) -> gamm…

EnergyBESIII Detector
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Determination of the number of J/psi events with J/psi -> inclusive decays

2012

The number of J/psi events collected with the BESIII detector at the BEPC II from June 12 to July 28, 2009 is determined to be (225.3 +/- 2.8) x 10(6) using J/psi -> inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.

PhysicsSystematic errorNuclear and High Energy PhysicsElectron–positron annihilationDetectorMonte Carlo methodBESIIIInclusive eventsAstronomy and AstrophysicsJ/ψ→Nuclear physicsBESIII detector; Inclusive events; J/ψ→; Number of J/ψ eventsNumber of J/ψ eventsJ/psi -> inclusive eventsnumber of J/psi eventsBESIII detectorInstrumentationChinese physics c
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