There has recently been a dramatic renewal of interest in hadron spectroscopy and charm physics. This renaissance has been driven in part by the discovery of a plethora of charmonium-like XYZ states at BESIII and B factories, and the observation of an intriguing proton-antiproton threshold enhancement and the possibly related X(1835) meson state at BESIII, as well as the threshold measurements of charm mesons and charm baryons. We present a detailed survey of the important topics in tau-charm physics and hadron physics that can be further explored at BESIII during the remaining operation period of BEPCII. This survey will help in the optimization of the data-taking plan over the coming years, and provides physics motivation for the possible upgrade of BEPCII to higher luminosity.

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Using a total of 9.0 fb −1 of e + e − collision data with center-of-mass energies between 4.15 and 4.30 GeV collected by the BESIII detector, we search for the processes e + e − → γX(3872) with X(3872) → π 0 χcJ for J = 0, 1, 2. We report the first observation of X(3872) → π 0 χc1, a new decay mode of the X(3872), with a statistical significance of more than 5σ. Normalizing to the previously established process e + e − → γX(3872) with X(3872) → π + π − J/ψ, we find B(X(3872) → π 0 χc1)/B(X(3872) → π + π − J/ψ) = 0.88 +0.33 −0.27 ±0.10, where the first error is statistical and the second is systematic. We set 90% confidence level upper limits on the corresponding ratios for the decays to π 0 χc0 and π 0 χc2 of 19 and 1.1, respectively.

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