Inclusive V production cross sections from 920 GeV fixed target proton-nucleus collisions

Abstract

Inclusive differential cross sections $d\sigma_{pA}/dx_F$ and $d\sigma_{pA}/dp_t^2$ for the production of K 0 S , $\Lambda$ , and $\bar{\Lambda}$ 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 $\sqrt{s} = 41.6$ GeV in the proton-nucleon system. The ratios of differential cross sections $d\sigma_{pA}$ (K $^{0}_{S})/d\sigma_{pA}(\Lambda)$ and $d\sigma_{pA}(\bar{\Lambda})/d\sigma_{pA}(\Lambda)$ are measured to be $6.2\pm 0.5$ and $0.66\pm 0.07$ , respectively, for xF $\approx\!-0.06$ . No significant dependence upon the target material is observed. Within errors, the slopes of the transverse momentum distributions $d\sigma_{pA}/dp_t^2$ also show no significant dependence upon the target material. The dependence of the extrapolated total cross sections $\sigma_{pA}$ on the atomic mass A of the target material is discussed, and the deduced cross sections per nucleon $\sigma_{pN}$ are compared with results obtained at other energies.