<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Λ</mml:mi></mml:math>polarization from unpolarized quark fragmentation

Abstract

The long-standing problem of explaining the observed polarization of $\ensuremath{\Lambda}$ hyperons, inclusively produced in the high-energy collisions of unpolarized hadrons, is tackled by considering spin- and ${\mathit{k}}_{\ensuremath{\perp}}$-dependent quark-fragmentation functions. The data on \ensuremath{\Lambda}'s and $\overline{\mathrm{\ensuremath{\Lambda}}}$'s produced in $p\ensuremath{-}N$ processes are used to determine simple phenomenological expressions for these new ``polarizing fragmentation functions,'' which describe the experiments remarkably well.