Pion and proton inclusive distributions in the diffractive-excitation model

The leading one-particle distributions for the inclusive reaction pp to cX (c=p, pi /sup +/) calculated in the diffractive-excitation model (DEM) are compared with the new CERN Intersecting Storage Rings data. For the pion distribution it is shown that a single Gaussian decay distribution, exp(- lambda k/sup 2/), even with the added assumptions of momentum conservation and off-axis scattering of the clusters, is unable to fit the data. It is then shown that a pion decay distribution given by a sum of two Gaussians does fit both the fixed-x and fixed-P/sub perpendicular to //sup 2/ distributions. The proton distributions are well fitted by a single Gaussian decay distribution. The proton spectrum exhibits a broad dip at x approximately=0.85 which is naturally explained in the DEM as protons emanating from a cluster (x<or approximately=0.8) and unexcited protons recoiling against a massive cluster (x>or approximately=0.9). (25 refs).