2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198268The decay mode $B_s\toψ\overline{K}^*$ is suggested as a very good way to measure the $B_s$ mixing parameter $x_s$. These decays can be gathered using a $ψ\to\ell^+\ell^-$ trigger. This final state has a well resolved four track decay vertex, useful for good time resolution and background rejection.Also available at http://fnpspa.fnal.gov/public_documents/psiks.psHigh Energy Physics - Experimenttext