We study the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$ using $5.1{\mathrm{fb}}^{-1}$ of data collected at 16 center-of-mass energy ($\sqrt{s}$) points from 4.008 to 4.600 GeV by the BESIII detector operating at the BEPCII collider. The measured Born cross sections for $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$ are consistent with previous results, but with much improved precision. A fit to the cross section shows contributions from two structures: the first has $M=4209.5\pm 7.4\pm 1.4\mathrm{MeV}/c^2$ and $\mathrm{\Gamma }=80.1\pm 24.6\pm 2.9\mathrm{MeV}$, and the second has $M=4383.8\pm 4.2\pm 0.8\mathrm{MeV}/{\mathrm{c}}^2$ and $\mathrm{\Gamma }=84.2\pm 12.5\pm 2.1\mathrm{MeV}$, where the first errors are statistical and the second systematic. The lower-mass resonance is observed in the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$ for the first time with a statistical significance of $5.8\sigma$. A charged charmoniumlike structure is observed in the ${\pi }^{\pm }\psi (3686)$ invariant mass spectrum for data at $\sqrt{s}=4.416\mathrm{GeV}$. A fit with an $S$-wave Breit-Wigner function yields a mass $M=4032.1\pm 2.4\mathrm{MeV}/c^2$, where the errors are statistical only. However, there are still unresolved discrepancies between the fit model and data. The width of the intermediate state varies in a wide range for different kinematic regions within the data set. Therefore, no simple interpretation of the data has been found, and a future data sample with larger statistics and more theoretical input will be required to better understand this issue.

• Received 27 March 2017

DOI:https://doi.org/10.1103/PhysRevD.96.032004