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arXiv · 1612.08159

The $Z_c(3900)$ peak does not come from the "triangle singularity"

Qin-Rong Gong·Jing-Long Pang·Yu-Fei Wang·Han-Qing Zheng
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Abstract

We compare contributions from the triangle diagram and the $D\bar D^*$ bubble chain to the processes of $e^{+}e^{-}\rightarrow J/ψπ^{+}π^{-}$ and $e^{+}e^{-}\rightarrow (D\bar D^*)^\mpπ^{\pm}$. By fitting the $J/ψπ$ maximum spectrum and the $D\bar D^*$ spectrum, we find that the triangle diagram cannot explain the new data from BESIII Collaboration at center of mass at 4.23GeV and 4.26GeV, simultaneously. On the contrary, the molecular assignment of $Z_c(3900)$ gives a much better description.

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Qin-Rong Gong, Jing-Long Pang, Yu-Fei Wang, Han-Qing Zheng. 2017-08-06. The $Z_c(3900)$ peak does not come from the "triangle singularity". https://arxiv.org/abs/1612.08159

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