Time dependent Bs mixing from lepton-kaon correlations with the ALEPH detector

Abstract

Searches for $B_s$ oscillations were made using data taken with the ALEPH detector in the years 1991--1994. Inclusive methods use leptons to tag the $B_s$ state at decay and to reconstruct the $B_s$ decay time. The $B_s$ state at production time is tagged either with a second lepton in the opposite hemisphere or a jet-charge algorithm. Also kaons from the fragmentation process were used to determine the initial state. Exclusive methods use $D_s$ or $D_s$-lepton events to reconstruct the $B_s$ at decay time. The initial state is inferred using leptons, jet charge or fragmentation kaons. No oscillations are observed and lower limits for the $B_s$ mass difference are obtained. A combined limit will be presented taking the correlations between the different analyses into account