Measurement of the branching fraction, polarization, and time-dependent $CP$ asymmetry in $B^0\to {\rho }^{+}{\rho }^{-}$ decays and constraint on the CKM angle ${\varphi }_2$

Belle II Collaboration, I. Adachi, L. Aggarwal +377

We present a measurement of the branching fraction and fraction of longitudinal polarization of $B^0\to {\rho }^{+}{\rho }^{-}$ decays, which have two ${\pi }^0$'s in the final state. We also measure…