Cross Section Measurement of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$ from $\sqrt{s}=4.0076$~GeV to 4.6984~GeV

Using data samples with a total integrated luminosity of $20.1\mathrm{f}{\mathrm{b}}^{-1}$ collected by the BESIII detector operating at the BEPCII collider, the cross section of the process $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$ is measured at center-of-mass energies between 4.0076 and 4.6984 GeV. The measured cross section is consistent with previous results, but with much improved precision. A fit to the measured energy-dependent cross section, which includes three Breit-Wigner functions and a non-resonant contribution, confirms the existence of the charmonium-like states $Y(4220)$, $Y(4390)$, and $Y(4660)$. This is the first observation of the $Y(4660)$ at the BESIII experiment.