Strange particle production in pp collisions at sqrt {s} = 0.9 and 7 TeV

The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The {text{K}}_{text{S}}^0 , Λ, and Ξ^- particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and transverse momentum, p _T. The results are compared to other experiments and to predictions of the P ythia Monte Carlo program. The p _T distributions are found to differ substantially from the P ythia results and the production rates exceed the predictions by up to a factor of three.