Search

Inclusive differential cross sections dσpA/dxF and dσpA/dpt² for the production of KS0, Λ, and Λ 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(KS0)/dσpA(Λ) and dσpA(Λ)/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/dpt² 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. [ABSTRACT FROM AUTHOR]

Using the HERA - B detector, the bb production cross section has been measured in 920 GeV proton collisions on carbon and titanium targets. The bb production was tagged via inclusive bottom quark decays into J/ψ by exploiting the longitudinal separation of J/ψ → l+l- decay vertices from the primary proton-nucleus interaction. Both e+e- and u+u- channels have been reconstructed and the combined analysis yields the cross section σ(bb) 32-12+14(stat)-7+6(sys) nb/nucleon. [ABSTRACT FROM AUTHOR]