Highlights of recent BESIII results (2311.14279v2)

Abstract: This report highlights the recent BESIII results related to the measurement of the $R$ value, radiative decays of $J/\psi$ and the polarization of $D^0 \to \omega \phi$ decay. BESIII, a symmetric electron-positron collider experiment, has collected a large data sample at several energy points in the tau-charm region, including the $J/\psi$ and $\psi(3770)$ resonances. Based on the data samples collected at 14 center-of-mass energy ($\sqrt{s}$) points between 2.2323 and 3.671 GeV, BESIII has achieved a measurement of the $R$ value with an accuracy down to the level of $2.6\%$ for $\sqrt{s} < 3.1$ GeV and $3.0\%$ for $\sqrt{s} > 3.1$ GeV. BESIII has also observed the $X(2600)$ resonance in radiative $J/\psi$ decay and the polarization of $D^0 \to \omega \phi$ for the first time. The polarization of $D^0 \to \omega \phi$ saturates with completely transverse polarization, which is inconsistent with the existing theoretical models. These results are useful in testing the predictions of the Standard Model.