Spin Polarization of Hyperons in the Hadron-hadron Inclusive Collisions

The high energy hadron-hadron collisions produce various hyperons, in which large spin polarizations perpendicular to a production plane are observed at high Feynman-x (xF ) and low transverse momentum pT . For these collisions, we have proposed a global model on the basis of quark rearrangements concept. In order to produce a final state hyperon at high xF , we consider possible rearrangement processes allowed by the SU(6) symmetry, where valence quarks (diquarks) from the injectile combine with sea quarks created from vacuum. Evaluation of rearrangement amplitudes in terms of relativistic quarks and diquarks with the confinement force in fact provides the spin asymmetry. We assume that the polarization is principally brought about by the rearrangement mechanism, while all other processes such as the standard fragmentation, which usually comes from showers of partons rather than the valence quark of the injectile and thus negligible at high xF , are spin-independent. If this concept would work for the various hadron productions, we can consistently apply it to evaluations of the spin observables by any injectile collisions.