Large samples of Lambda, Sigma(1385) and Xi(1321) hyperons produced in the deep-inelastic muon scattering off a (LiD)-Li-6 target were collected with the COMPASS experimental setup at CERN. The relative yields of Sigma(1385)(+), Sigma(1385)(-), Sigma(1385)(-), Sigma(1385)(+), Xi(1321)(-), and Xi(1321)(+) hyperons decaying into Lambda(Lambda)pi were measured.
The ratios of heavy-hyperon to Lambda and heavy-antihyperon to Lambda were found to be in the range 3.8 % to 5.6 % with a relative uncertainty of about 10 %. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.