Atomic-Number Dependence of Large-Transverse-Momentum Hadron Production by Protons

We have measured at Fermilab the production of hadrons at {~}90^∘{} in the c.m. system as a function of incident proton energy, atomic number A of the production target, and the transverse momentum p_⊥ of the produced hadron. The A dependence of the production cross section of the hadrons can be described by a function A^∝(p_⊥), where the power α rises with p_⊥. At p_⊥ ~5 GeV/c, α is {~}1.1 for π^± and K⁺, and {~}1.3 for p, p̄, and K^-. The energy dependence of the power is also measured.