K*0 and φ meson production in proton–nucleus interactions at

The inclusive production cross sections of the strange vector mesonsK *0 , K *0 , and φ have been measured in interactions of 920 GeV protons with C, Ti, and W targets with the HERA-B detector at the HERAstorage ring. Differential cross sections as a function of rapidity and transverse momentum have been measured in the central rapidity region and for transverse momenta up to p T = 3.5 GeV/ c . The atomic number dependence is parametrised as σ pA =σ pN *A α , where σ pN is the proton–nucleon cross section. Within the phase space accessible, α(K *0 )=0.86±0.03, α(K *0 )=0.87±0.03, and α(φ)=0.96±0.02. The total proton–nucleon cross sections, determined by extrapolating the differential measurements to full phase space, are σ pN→K*0 =(5.06±0.54) mb, σ pN→K*0 =(4.02±0.45) mb, and σ pN→φ =(1.17±0.11) mb. For all resonances the Cronin effect is observed; compared to the measurements of Cronin et al. for K ± mesons, the measured values of α for φ mesonscoincide with those of K + mesonsfor all transverse momenta, while the enhancement for K *0 /K *0 mesonsis smaller.