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Study of $B^0_s$ oscillations and lifetime using fully reconstructed $D_s$ - decays

Research output: Contribution to journalJournal article

Published

Journal publication date07/1998
JournalThe European Physical Journal C (EPJ C) - Particles and Fields
Journal number3
Volume4
Number of pages19
Pages367-385
Original languageEnglish

Abstract

A search for B0s oscillations is performed using approximately 4 million Z→qq¯ events collected by the ALEPH experiment during 1991–1995. B0s candidates are partially reconstructed by combining tracks with fully reconstructed D−s candidates. The B0s production flavour is estimated from the sign of the opposite hemisphere charge, a fragmentation kaon in the same hemisphere, or a lepton in the opposite hemisphere. From a total sample of 1620 candidates, with a B0s purity estimated to be 22%, all values of Δms below 3.9 ps −1 and between 6.5 and 8.8 ps −1 are excluded at 95% CL. From the same sample, the B0s lifetime is measured to be τs=1.47±0.14(stat)±0.08(syst) ps. This analysis selects mainly hadronic B0s decays and is statistically independent of a previous ALEPH analysis selecting B0s→D(∗)−sℓ+ν candidates. Combining these two analyses yields Δms>7.9 ps −1 at 95% CL and τs=1.51±0.11 ps.