Prospects for $B_{(s)}^0\to {\pi }^0{\pi }^0$ and $B_{(s)}^0\to \eta \eta$ modes and corresponding $CP$ asymmetries at Tera-$Z$

Yuexin Wang, Sébastien Descotes-Genon, Olivier Deschamps +4

The physics potential of measuring $B_{(s)}^0\to {\pi }^0{\pi }^0$ and $B_{(s)}^0\to \eta \eta$ decays via four-photon final states at Tera-$Z$ phase of CEPC or FCC-ee is investigated in this paper.…