New graph-neural-network flavor tagger for Belle II and measurement of $\sin 2{\varphi }_1$ in $B^0\to J/\psi K_{\text{S}}^0$ decays

Belle II Collaboration, I. Adachi, L. Aggarwal +413

We present GFlaT, a new algorithm that uses a graph-neural-network to determine the flavor of neutral $B$ mesons produced in ${\rm Y}(4S)$ decays. It improves previous algorithms by usin…