Lambda polarization from unpolarized quark fragmentation

The long-standing problem of explaining the observed polarization of Lambda hyperons, inclusively produced in the high-energy collisions of unpolarized hadrons, is tackled by considering spin- and k(perpendicular to)-dependent quark-fragmentation functions. The data on Lambda 's and )over bar>'s produced in p-N processes are used to determine simple phenomenological expressions for these new "polarizing fragmentation functions," which describe the experiments remarkably well.