Evidence for the decay $B^0\to \eta \eta$

A. Abdesselam, I. Adachi, K. Adamczyk +447

We report a search for $B^0\to \eta \eta$ with a data sample corresponding to an integrated luminosity of $698{\mathrm{fb}}^{-1}$ containing $753\times 10^6$ $B\bar{B}$ pairs collected…