Precise measurement of the CKM angle $\gamma$ with a novel approach

A measurement of the CKM angle $\gamma$ is performed by applying a novel, unbinned, model-independent approach to datasets of electron-positron collisions collected by the BESIII experiment and proton-proton collisions by the LHCb experiment, corresponding to integrated luminosities of 8 fb${}^{-1}$ and 9 fb${}^{-1}$, respectively. The $C\text{\hspace{0.17em}⁣}P$-violating phase $\gamma$ is determined from $B^{\pm }\to D(\to K_{\mathrm{S}}^0{h}^{\mathrm{\prime }+}{h}^{\mathrm{\prime }-})h^{\pm }$ decays in LHCb data, where $h^{(\mathrm{\prime })}$ is either a pion or kaon, while the corresponding strong-phase parameters are measured using doubly tagged $D\to K_{\mathrm{S}\mathrm{/}\mathrm{L}}^0{h}^{\mathrm{\prime }+}{h}^{\mathrm{\prime }-}$ decays in the quantum-correlated $D\bar{D}$ system present in BESIII data. A joint fit to both datasets, which allows for a simultaneous determination of the associated $C\text{\hspace{0.17em}⁣}P$-violating observables and strong-phase parameters, yields $\gamma =(71.3\pm 5.0{)}^{\circ }$. The result is the most precise to date and consistent with previous measurements and world averages.