https://doi.org/10.1140/epjc/s2004-01827-0
experimental physics
Search for 
- 
oscillations in DELPHI using high-p
t
leptons
Oscillations in the B
0
s
- 
system were studied in events selected from about 4.3 million hadronic Z0 decays registered by DELPHI between 1992 and 2000. This paper presents updates of two published analyses ([11, 12]). The first analysis, which utilizes leptons emitted with large momentum transverse to a jet, was improved by means of a better algorithm for the vertex reconstuction and a new algorithm for flavour-tagging at production time. The second analysis, which utilizes D
s
-lepton events, was improved by optimizing the treatment of proper time resolution. No signal of B
0
s oscillations was observed and limits on the mass difference between the physical B
0
s
states were obtained to be: 
in the high p
t
lepton analysis and 
in the D
s
-lepton analysis. Previously published results on these analyses are superseded. The combination of these results with those obtained in other independent analyses previously performed in DELPHI (D
s
-hadron, exclusive B
s
0, inclusive vertex) gives: 
© Springer-Verlag, 2004
