Inclusive distributions for hadronic collisions in the valon-recombination model

Inclusive distributions of soft production of mesons in hadronic collisions are calculated in the valon-recombination model. The new determination of the valon distributions from hard scattering data makes possible a tightly interrelated treatment of pion and kaon production in the fragmentation regions of proton, pion, and kaon. Only one free parameter is used in the determination of the valon distribution in the kaon. No other adjustable parameter is needed to fit the x distributions of the data on inclusive cross sections, except for the normalizations since the data are at fixed $p_T.$ The success of the model in reproducing seven inclusive distributions suggests that there are two important mechanisms at work in soft production. One is that the structure of the hadron that fragments is highly relevant. The other is that the produced particles are formed by the recombination of quarks and antiquarks. These two aspects about hadrons in soft processes can be well described in the framework of the valon-recombination model.