Recent Results on Isospin-Violating Transitions in Charmonium Studied with BESIII

Charmonium spectroscopy provides strong guidelines to effective field theories, thereby gaining insight into quark confinement and the generation of hadron masses. Hadronic transitions between charmonium states have been measured with unprecedented high precision with the BESIII spectrometer at IHEP Beijing, China. We present systematic studies of isospin-violating decays in charmonium, such as $\psi' \rightarrow \pi^{0} J/\psi$, $\psi' \rightarrow \pi^{0} h_{c}$, $e^{+}e^{-} \rightarrow \pi^{0} J/\psi$ at $\sqrt{s}=$ 4.009 GeV, and their improved measurements of their branching fractions.