Production asymmetry of D s from 600 GeV/ c Σ − and π − beam

The production of D s − relative to D s + as a function of x F with 600 GeV/ c Σ − beam is measured in the interval 0.15 x F c Σ − beam (0.53±0.06) and π − beam (0.06±0.11) are also compared. The results show the Σ − beam fragments play a role in the production of D s − , as suggested by the leading quark model.