Measurement of $e^{+}e^{-} \to \pi^{0}\pi^{0}\psi(3686)$ at $\sqrt{s}$ from 4.009 to 4.600 GeV and observation of a neutral charmoniumlike structure

TL;DR

This study measures the cross sections of the process $e^{+}e^{-} o ext{pi}^0 ext{pi}^0 ext{psi}(3686)$ across energies from 4.009 to 4.600 GeV, observing a neutral charmoniumlike structure consistent with isospin symmetry.

Contribution

First measurement of $e^{+}e^{-} o ext{pi}^0 ext{pi}^0 ext{psi}(3686)$ cross sections and observation of a neutral structure analogous to a known charged state.

Findings

Cross sections are half of those for charged mode, consistent with isospin symmetry.

Dalitz plots match those of charged mode across energies.

Neutral structure observed at 4040 MeV/$c^{2}$, similar to charged counterpart.

Abstract

Using $e^{+}e^{-}$ collision data collected with the BESIII detector at the BEPCII collider corresponding to an integrated luminosity of 5.2 $fb^{-1}$ at center-of-mass energies ($\sqrt{s}$) from 4.009 to 4.600 GeV, the process $e^{+}e^{-} \to \pi^{0} \pi^{0}\psi(3686)$ is studied for the first time. The corresponding Born cross sections are measured and found to be half of those of the reaction $e^{+}e^{-} \to \pi^{+}\pi^{-}\psi(3686)$. This is consistent with the expectation from isospin symmetry. Furthermore, the Dalitz plots for $\pi^{0}\pi^{0}\psi(3686)$ are accordant with those of $\pi^{+}\pi^{-}\psi(3686)$ at all energy points, and a neutral analogue to the structure in $\pi^\pm \psi(3686)$ around 4040 MeV/$c^{2}$ first observed at $\sqrt{s}$=4.416 GeV is observed in the isospin neutral mode at the same energy.