Eur. Phys. J. Special Topics 162, 147-153 (2008)
https://doi.org/10.1140/epjst/e2008-00788-5

The challenge of polarizations in hadronic hyperon production

Physikalisches Institut, Universität Heidelberg (), Institut für Kernphysik, Universität Mainz, Germany

Abstract

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 p_t at values below ≈1 GeV/c as observed for other hyperon polarizations, it vanishes above  GeV/c. Such a breakdown at large p_t has not been observed in any other beam/hyperon combination.