The production of ${\mathrm{\pi }}^{\pm }$,${\mathit{K}}^{\pm }$,p has been measured in p+Be and p+Au collisions for comparison with central Si+Au collisions. The inverse slope parameters ${\mathit{T}}_0$ obtained by an exponential fit to the invariant cross sections in transverse mass are found to be, ${\mathit{T}}_0^{\mathit{p},}$${\mathit{K}}^{+}$,${\mathrm{\pi }}^{\mathrm{\pi }}$∼140–160 MeV in p+A collisions, whereas in central Si+Au collisions, ${\mathit{T}}_0^{\mathit{p},}$${\mathit{K}}^{+}$∼200–220 MeV >${\mathit{T}}_0^{\mathrm{\pi }\mathrm{\pi }}$∼140–160 MeV at midrapidity. The ${\mathrm{\pi }}^{\pm }$ and ${\mathit{K}}^{+}$ distributions are shifted backwards in p+Au compared with p+Be. A gradual increase of (dn/dy${)}_{\mathit{K}}^{+}$ per projectile nucleon is observed from p+Be to p+Au to central Si+Au collisions, while pions show no significant increase.

• Received 19 October 1990

DOI:https://doi.org/10.1103/PhysRevLett.66.1567