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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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In an analysis of a 2.92 fb −1 data sample taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we measure the absolute decay branching fractions B(D 0 → K − e + νe) = (3.505 ± 0.014 ± 0.033)% and B(D 0 → π − e + νe) = (0.295 ± 0.004 ± 0.003)%. From a study of the differential decay rates we obtain the products of hadronic form factor and the magnitude of the CKM matrix element f ), we determine the ratio |V cd |/|Vcs| = 0.238 ± 0.004 ± 0.002 ± 0.011, where the third error is from the uncertainty in the LCSR normalization. In addition, we measure form factor parameters for three different theoretical models that describe the weak hadronic charged currents for these two semileptonic decays. All of these measurements are the most precise to date.