A new expected upper limit on the rare decay Bs → μ+μ- with the D0 experiment

We present a new expected upper limit of the rare decay branching ratio Bs → μ+μ- using about 5 fb-1 of Run II data collected with the D0 detector at the Tevatron. When setting limits on the branching ratio, selected events are normalized to reconstructed B± → J/ΨK± events in order to decrease the systematic uncertainty. The resulting expected upper limit is Β(Bs → μ+μ-) = 4.3(5.3) x 10-8 at the 90% (95%) C.L.