The challenge of polarizations in hadronic hyperon production
Physikalisches Institut, Universität Heidelberg (),
Institut für Kernphysik, Universität Mainz, Germany
The large amount of data on hyperon polarizations in inclusive production by hadrons at high energies has recently been extended to Λ and production by beams. The sign of the polarization is negative and the same as in Λ and production by protons. The sign of the Λ polarization, however, is positive, in contrast to the negative sign expected by analogy to the proton beam data for Λ and polarization. Theoretical expectations, for instance from a recombination model, also favoured negative polarization of Λ produced by . Moreover, while the Λ polarization increases with pt at values below ≈1 GeV/c as observed for other hyperon polarizations, it vanishes above GeV/c. Such a breakdown at large pt has not been observed in any other beam/hyperon combination.
© EDP Sciences, Springer-Verlag, 2008