Topological pomeron andA-universality

Abstract

The nuclear mass number dependence of inclusive spectra of secondaries with different quantum numbers in the projectile fragmentation region is analysed. We note that in models with topological pomeron, all the particle spectra fall into two main categories. The first one comprises particles which have a common “valence” quark with the projectile, the second one comprises all the other particles built of “sea” quarks. Thus, in the parameterization$x\frac{{d\sigma }}{{dx}} \propto A^{\alpha (x)}$ the spectra of all “valence” hadrons (p, n, Λ, π^+,0,−,K ⁺, ... in thepA-interaction) atx→1 can be characterized by the single exponent α_υ =α(x≊1) which differs slightly from α _s characterizing the spectra of “sea” hadrons ($\bar p, \bar \Lambda$,K ⁻, ... forpA-interactions). This observation is essentially modelindependent and follows only from the topological structure of the pomeron and Gribov's space-time picture of soft hadronic interactions. Deviations from universality due to preasymptotic corrections and coherent particle production processes are estimated.