Model-Independent phase correction in $D\rightarrow K_S\pi^+\pi^-$ decays for the precise measurement of CKM angle $\gamma$ in $B^\pm\rightarrow DK^\pm$ transition

by Shenghui Zeng (University of Bristol)

Wednesday 9 Apr 2025, 10:00 → 11:00 Europe/Berlin

CP-03-123 (TU Dortmund)

Precise determination of the Cabibbo-Kobayashi-Maskawa angle $\gamma$ is a key goal in testing the Standard Model. This talk presents a novel unbinned model-independent method for measuring $\gamma$ using $B^\pm \rightarrow DK^\pm$ decays, where $D \rightarrow K_S \pi^+ \pi^-$. The method uses the data-driven decay-amplitude phases derived from quantum-correlated charm threshold data from the BESIII experiment. It therefore removes the unavoidable model assumptions of the $D$ decay amplitude, which is an important source of systematic uncertainty and is hard to estimate. This unbinned approach can also make full use of the information in the $D$ decay phase space. Using the simulated data samples of $B^\pm \rightarrow DK^\pm$ decays and quantum-correlated $D \rightarrow K_S \pi^+ \pi^-$ decays, we demonstrate that this method achieves a statistical precision on $\gamma$ of 4.65 degrees, with a charm-related systematic uncertainty contribution of only 0.3 degrees.