Hyperon Polarization in a Quark-Quark Scattering Model

A continuing mystery in particle physics is the large polarization observed in inclusive hyperon production in high energy proton-proton collisions. Both the inclusive nature of the process and the high energies involved make the observation of huge spin effects very surprising. In this paper the authors advance the concept that the polarization effects can be accounted for in a simple model based on quarks becoming polarized in the direct q-q scattering process and where, at a fundamental level, the s quark is treated no differently than the u and d, except that it is required to have been created as part of a s− s̄ pair prior to the collision. The q-q polarization parameters are extracted from p-p elastic scattering using a previous model and these are used to predict the Λ polarization from the p-p data. Remarkably good agreement is obtained, raising the possibility that the large hyperon polarizations are no more of a mystery than the p-p polarization itself and that, at least at small pt , the two may be simply related. This concept is extended in an attempt to explain the polarizations observed in other inclusive hyperon processes with the finding that hyperon and elastic polarizations, which previously seemed almost unrelated, may have a simple and common origin.