Transverse Polarisation of Λ and Λ Hyperons in Quasi-Real Photon Nucleon Scattering

摘要

The transverse polarisation in inclusively produced Λ and Λ hyperons has been studied at HERMES using the 27.5 GeV positron beam of the HERA accelerator at DESY. The average transverse polarisations were found to be P_n~Λ = 0.055 +- 0.006 (stat) +- 0.016 (syst) and P_n~Λ = -0.043 +- 0.013 (stat) +- 0.012 (syst) for Λ and Λ, respectively. The dependence of P_n~Λ and P_n~Λ on the transverse momentum p_T and on the hyperons' light-cone momentum fraction ζ has been investigated. The measured polarisations for Λ and Λ exhibit different behavior in the current and target fragmentation regions.