Article révisé par les pairs
Résumé : An attempt at the direct observation of the cascade decay of beauty particles, produced by π- of 350 GeV/c leading to 3 muons or 4 muons in the final state, has been made in an emulsion/counter hybrid experiment at CERN. Under the assumption that the lifetime of beauty particles is of the order of 10-13s the non-observation of any candidates provides an upper limit for beauty production of ∼90 nb at the 90% confidence level.