V 0 production in p+A collisions at GeV

Inclusive doubly differential cross sections d 2 σ pA / dx F dp T 2 as a function of Feynman-x ( x F ) and transverse momentum ( p T ) for the production of K S 0 , Λ and in proton-nucleus interactions at 920 GeV are presented. The measurements were performed by HERA-B in the negative x F range (−0.12 x F p T =1.6 GeV/ c . Results for three target materials: carbon, titanium and tungsten are given. The ratios of production cross sections are presented and discussed. The Cronin effect is clearly observed for all three V 0 species. The atomic numberdependence is parameterized as σ pA = σ pN ⋅ A α where σ pN is the proton-nucleon cross section. The measured values of α are all near one. The results are compared with EPOS 1.67 and PYTHIA 6.3. EPOS reproduces the data to within ≈20% except at very low transverse momentum.