Search for the decay ▫$B_s^0 \to \eta \eta$▫Bhuyan, S. (Avtor) Biswal, Jyoti Prakash (Avtor) Bračko, Marko (Avtor) Golob, Boštjan (Avtor) Korpar, Samo (Avtor) Križan, Peter (Avtor) Pestotnik, Rok (Avtor) Starič, Marko (Avtor) Šantelj, Luka (Avtor) We report results from a search for the decay B0s→ηη using 121.4  fb−1 of data collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We do not observe any signal and set an upper limit on the branching fraction of 14.3×10−5 at 90% confidence level. This result represents a significant improvement over the previous most stringent limit.20222023-08-17 09:43:16Znanstveno delo85053sl