Anomalous Line-Shape of Cross Sections for $e^+e^- \to {\rm Hadrons}$ in the Center-of-Mass Energy Region between 3.650 and 3.872 GeV

BES Collaboration

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arXiv · 0807.0494

Anomalous Line-Shape of Cross Sections for $e^+e^- \to {\rm Hadrons}$ in the Center-of-Mass Energy Region between 3.650 and 3.872 GeV

BES Collaboration

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Abstract

We observe an obvious anomalous line-shape of the $e^+e^- \to {\rm hadrons}$ total cross sections in the energy region between 3.700 and 3.872 GeV from the data samples taken with the BES-II detector at the BEPC Collider. Re-analysis of the data shows that it is inconsistent with the explanation for only one simple $\psi(3770)$ resonance with a statistical significance of $7\sigma$. The anomalous line-shape may be explained by two possible enhancements of the inclusive hadron production near the center-of-mass energies of 3.764 GeV and 3.779 GeV, indicating that either there is likely a new structure in addition to the $\psi(3770)$ resonance around 3.773 GeV, or there are some physics effects reflecting the $D\bar D$ production dynamics.

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BES Collaboration. 2008-07-03. Anomalous Line-Shape of Cross Sections for $e^+e^- \to {\rm Hadrons}$ in the Center-of-Mass Energy Region between 3.650 and 3.872 GeV. https://arxiv.org/abs/0807.0494

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