Speaker
Description
Precision measurements of the CKM angle $\gamma$ provide a theoretically clean test of the unitarity of the CKM matrix and are therefore a powerful probe for physics beyond the Standard Model. Despite significant experimental progress, $\gamma$ remains one of the least precisely determined CKM parameters, with current measurements dominated by statistical uncertainties. This makes $\gamma$ measurements particularly sensitive to both increased data samples and improvements in analysis techniques.
In this talk, I will present the first measurement of $\gamma$ and related CP observables using $B^{\pm}\!\to D(\to K^0_S h^{\prime+} h^{\prime-})\,h^{\pm}$ decays with data collected during Run~3 of the LHC using the upgraded LHCb detector. The higher instantaneous luminosity and the software-only trigger of the LHCb Upgrade significantly enhance the efficiency for such hadronic final states, enabling this single year of data-taking alone to provide one of the dominant inputs to the global $\gamma$ combination.
Looking to future measurements, I will present recent developments in the optimisation of Dalitz-plot binning schemes used in model-independent $\gamma$ measurements. A revised optimisation metric, directly related to the statistical precision on $\gamma$, is introduced, together with improvements that account for realistic experimental effects such as backgrounds and binning-dependent systematic uncertainties. Sensitivity studies demonstrate an improvement of approximately $5\%$ in the expected precision on $\gamma$ in $B^{\pm}\!\to D(\rightarrow K_S^0\pi^+\pi^-)K^{\pm}$ decays compared to the previously used binning scheme.
In addition, the optimisation framework is extended to measurements of CP violation in charm mixing using $D\to K^0_S\pi^+\pi^-$ decays, where a dedicated optimal binning scheme is derived for the first time. Sensitivity studies show a substantial improvement of approximately $25\%$ relative to the equal-phase binning currently in use.