Measurements of ${\mathrm{\Xi }}^{-}$ and ${\bar{\mathrm{\Xi }}}^{+}$ production in proton-proton interactions at $\sqrt{s_{NN}}$ = 17.3 GeV in the NA61/SHINE experiment

The production of $\mathrm{\Xi }(1321{)}^{-}$ and $\bar{\mathrm{\Xi }}(1321{)}^{+}$ hyperons in inelastic p+p interactions is studied in a fixed target experiment at a beam momentum of 158 GeV/textit{c}. Double differential distributions in rapidity y and transverse momentum $p_T$ are obtained from a sample of 33M inelastic events. They allow to extrapolate the spectra to full phase space and to determine the mean multiplicity of both ${\mathrm{\Xi }}^{-}$ and ${\bar{\mathrm{\Xi }}}^{+}$. The rapidity and transverse momentum spectra are compared to transport model predictions. The ${\mathrm{\Xi }}^{-}$ mean multiplicity in inelastic p+p interactions at 158~\GeVc is used to quantify the strangeness enhancement in A+A collisions at the same centre-of-mass energy per nucleon pair.