Strangeness production in pp and pn reactions at COSY

Abstract

The cooler synchrotron COSY-Jülich delivers phase-space cooled, polarized proton and deuteron beams with momenta up to p = 3.65 GeV / c . Various experiments on hadron-induced strangeness production on proton, neutron and nuclear targets have been carried out. Here we report recent results on associated strangeness production in p p → K Y N ( Y = Λ , Σ ) reactions, on K + -production in pn collisions, and on K K ¯ -pair production in pp interactions. We also briefly discuss possible measurements to disentangle the parity of the recently discovered pentaquark state Θ + , the spin dependence of the YN interaction, as well as planned experiments which aim at the determination of the a 0 – f 0 mixing matrix element, a quantity which is believed to be sensitive to the nature of the light scalar mesons a 0 / f 0 ( 980 ) .