Speaker
Florian Hauenstein
(Old Dominion University)
Description
The associated strangeness production in pp interactions has been studied with the COSY-TOF detector in the reaction $\vec{p}p \to
pK^{+}\Lambda$ close to threshold at the COSY accelerator at the research center Juelich in Germany. The underlying reaction mechanisms are not fully understood since perturbative QCD calculations can not be applied at this energy regime. What has been determined so far is a strong influence of $N^{*}$ resonances in the reaction, a strong $p\Lambda$ final state interaction and a $N\Sigma - p\Lambda$ channel coupling which leads to an cusp effect in the $p\Lambda$ invariant mass spectrum.
The latest measurements at COSY-TOF have been carried out with a polarized proton beam. This allows also the determination of polarization observables such as the spin transfer of the beam to the $\Lambda$ or the beam analyzing power measured with the final state particles. These polarization observables could improve the understanding of the reaction mechanism further. Furthermore, the $p\Lambda$ final state interaction is used to extract information about the bare $p\Lambda$ interaction. It is possible to determine model-independently the spin triplet scattering length utilizing the analyzing power from the Kaon asymmetry.
In the HYP2015 conference in Sendai, Japan preliminary results on the scattering length and the various polarization observables were presented. In my talk I will show the final, published results and give a discussion about the statistical and systematic errors and a comparison with existing data.
Primary author
Florian Hauenstein
(Old Dominion University)
