Pion Production in Proton-Proton Collision and a Unified Description of Inclusive Spectra

Abstract

The inclusive reactions pp-+rr+, rr- and rr' X are systematically analyzed in terms of a unified formula for single-particle distribution function. These processes are characterized by two components of production mechanism, i.e., fragment and central production mechanisms which are mapped on the H®P-type and P®P-type bond· diagrams. The former and latter mechanisms are dominant in the large and small energy fraction regions, respectively. The ratio rr+ /rr- on the entire Peyrou plot is naturally explained. § 1. Introduction and summary Recently, from the viewpoint of composite structure of hadrons a unified de­ scription of the single-particle distribution function has been proposed.v Hadrons are described by the minimum urbaryon number (valence urbaryon number), and reaction mechanism is characterized by the flow of valence urbaryons which is mapped on the bond diagrams.2l The unified description is given by the whole­ region formula, which incorporates smooth transition between soft collision at small Pr(pr 2GeV/c), wherePr denotes the transverse momentum. In this paper, we present the systematic analyses of inclusive reactions PP-77r+, n- and n°X in terms of the unified description 'of the single-particle-spectrum. These processes are characterized by the two components of produc­ tion mechanism, i.e., fragment and central production mechanisms which are described by the H@P-type and P@P-type bond diagrams as shown in Fig. 1. At small Pr ,regions, the H@P-type mechanism exhibits the limiting behaviour and the P®P-type one