Observation of the Anomalous Shape of $X(1840)$ in $J/\psi \to \gamma 3({\pi }^{+}{\pi }^{-})$ Indicating a Second Resonance Near $p\bar{p}$ Threshold

BESIII Collaboration, M. Ablikim, M. N. Achasov +615

Using a sample of $(10087\pm 44)\times 10^6$ $J/\psi$ events, which is about 45 times larger than that was previously analyzed, a further investigation on the $J/ψ\rightarrow γ3(π^+π^-…