Inclusive V0 production cross sections from 920 GeV fixed target proton-nucleus collisions: The HERA-B Collaboration

Inclusive differential cross sections dσpA/dxF and dσpA/dpt 2 for the production of Ks 0, Λ, and Λ̄ particles are measured at HERA in proton-induced reactions on C, Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to √s = 41.6 GeV in the proton-nucleon system. The ratios of differential cross sections dσpA(Ks 0)/dσpA(Λ) and dσpA(Λ̄)/dσpA(Λ) are measured to be 6.2 ± 0.5 and 0.66 ± 0.07, respectively, for xF ≈ -0.06. No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions dσpA/dpt 2 also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections σpA on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon σPN are compared with results obtained at other energies.