Measurement of the CKM angle $\gamma$ in $B^{\pm }\to D(\to K_{\mathrm{S}}^0{h}^{\mathrm{\prime }+}{h}^{\mathrm{\prime }-})h^{\pm }$ decays with a novel approach

A measurement of the CKM angle $\gamma$ and related strong-phase parameters is performed using a novel, model-independent approach in $B^{\pm }\to D(\to K_{\mathrm{S}}^0{h}^{\mathrm{\prime }+}{h}^{\mathrm{\prime }-})h^{\pm }$ decays, where $h^{(\mathrm{\prime })}\equiv \pi ,K$. The analysis uses a joint data sample of electron-positron collisions collected by the BESIII experiment at the Beijing Electron-Positron Collider II during 2010–2011 and 2021–2022, corresponding to an integrated luminosity of 8 fb${}^{-1}$, and proton-proton collisions collected by the LHCb experiment at the Large Hadron Collider during 2011–2018, corresponding to an integrated luminosity of 9 fb${}^{-1}$. The two datasets are analyzed simultaneously by applying per-event weights based on the amplitude variation over the $D$-decay phase space to enhance the sensitivity to $C\text{\hspace{0.17em}⁣}P$-violating observables. The CKM angle $\gamma$ is determined to be $\gamma =(71.3\pm 5.0{)}^{\circ }$, which constitutes the most precise single measurement to date.