We study initial-state radiation events, e+e- -> gamma_ISR pi+ pi- J/psi, with data collected with the BABAR detector. We observe an accumulation of events near 4.26 GeV/c2 in the invariant-mass spectrum of pi+ pi- J/psi. Fits to the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c2 is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/c2, depending on the fit hypothesis.

Observation of a broad structure in the pi+ pi- J/Psi mass spectrum around 4.26 GeV/c2


 N. Cavallo;F. Fabozzi;
2005

Abstract

We study initial-state radiation events, e+e- -> gamma_ISR pi+ pi- J/psi, with data collected with the BABAR detector. We observe an accumulation of events near 4.26 GeV/c2 in the invariant-mass spectrum of pi+ pi- J/psi. Fits to the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c2 is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/c2, depending on the fit hypothesis.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11563/16547
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