Longitudinal polarisation of Λ and Λ̄ hyperons in lepton–nucleon deep-inelastic scattering J. Ellis, A. Kotzinian, D. Naumov and M. Sapozhnikov Eur. Phys. J. C, 52 2 (2007) 283-294 Published online: 15 August 2007 DOI: 10.1140/epjc/s10052-007-0381-9