Polarization of lambda Hyperons Produced in Pp Collisions at 19 GeV/C

摘要

The polarization of the lambda hyperon produced in the inclusive reaction p+p implies lambda +X is measured at 19 GeV/c with a sample of 4975 lambda 's. Nonzero values of the polarization are observed for lambda 's with transverse momentum larger than 0.6 GeV/c. Somewhat weaker indications of a nonzero effect are seen for values of the Feynman variable alpha x alpha larger than 0.8. The triple-Regge formula with only leading K* and K** trajectories predicts vanishing polarization and is consistent with data at alpha x alpha