String model description of polarisation and angular distributions in $\mth{\overline{p}p\rightarrow\overline{\Lambda}\Lambda}$ at low energies

The observed polarisation of $\Lambda$ hyperons from the inclusive $pA \rightarrow \Lambda X$ reaction at high energies has previously been well described within the Lund string model through polarised $s\bar{s}$ quark pair production in the string breaking hadronisation process. This model is here applied to the exclusive $\overline{p}p\rightarrow\overline{\Lambda}\Lambda$ $\overline{p}p\rightarrow\overline{\Lambda}\Lambda$ reaction at low energies and compared to available data sets down to an incident-beam momentum of 1.835 GeV/$c$. This required an extension of the diquark scattering model to involve three components: an isotropic part relevant close to the threshold, a spectator part and a forward-scattering part as in $pA \rightarrow \Lambda X$ at high energies. The observed angular distributions are then reproduced and, for momentum transfers above $|t'| = 0.2$ GeV$^{2}$, agreement with the measured polarisation is also obtained