Inclusive hadronic production cross sections measured in proton-nucleus collisions at√s =27.4GeV

We present results on the production of hadrons in collisions of 400-GeV/c protons with beryllium, copper, and tungsten nuclei. The data cover the region from 5.6 to 8.0 GeV/c in the transverse momentum of the final-state hadron and from 73° to 102° in the proton-nucleon center-of-momentum frame production angle ${\mathrm{theta}}^{\mathrm{*}}$. The restriction of the data to values of $x_T$ ($x_T$=2$p_T$/ √s ) greater than 0.4 enriches the sample with hard collisions of valence quarks. Asymmetries about ${\mathrm{theta}}^{\mathrm{*}}$=90° reflect the presence of neutrons in the target nuclei. The variation of the atomic-weight dependence parameter α with production angle is discussed in the context of the phenomenology of nucleonic structure within nuclei. We also extrapolate our measurements to a ‘‘deuteron’’ target to minimize nuclear effects and compare the result to QCD calculations.