Strange particle production in proton-proton collisions at √s=0.9 with ALICE at the LHC

Abstract

The production of mesons containing strange quarks (K⁰_S, φ) and both singly and doubly strange baryons (Λ, Λ̅, and Ξ⁻+Ξ̅⁺) are measured at mid-rapidity in pp collisions at √s=0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at mid-rapidity for inelastic pp collisions are presented. For mesons, we report yields ( < dN/dy > ) of 0.184±0.002(stat.)±0.006(syst.) for K⁰_S and 0.021±0.004(stat.)±0.003(syst.) for φ. For baryons, we find < dN/dy > =0.048±0.001(stat.)±0.004(syst.) for Λ, 0.047±0.002(stat.)±0.005(syst.) for Λ̅ and 0.0101±0.0020(stat.)±0.0009(syst.) for Ξ⁻ +Ξ̅⁺. The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.