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arXiv · 0707.2541

Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle

Belle Collaboration·C. Z. Yuan
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Abstract

The cross section for e^+e^- to pi^+pi^-J/psi between 3.8 and 5.5 GeV/c^2 is measured using a 548 fb^{-1} data sample collected on or near the Upsilon(4S) resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y(4260), is observed. In addition, there is another cluster of events at around 4.05 GeV/c^2. A fit using two interfering Breit-Wigner shapes describes the data better than one that uses only the Y(4260), especially for the lower mass side of the 4.25 GeV enhancement.

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Belle Collaboration, C. Z. Yuan. 2007-09-21. Measurement of e^+e^- to pi^+pi^-J/psi Cross Section via Initial State Radiation at Belle. https://doi.org/10.1103/physrevlett.99.182004

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