A unified approach for hadronic and nuclear collisions: the dual parton model

Exchange mechanisms of hadronic reactions

“…Thus at present energies a perturbative expansion in the small parameter (gpp~/16.rrcu~) ln(s) = 0.01 ln(s) is relevant with single Pomeron exchange dominating. To fit the rise in cross sections it is necessary to take the Pomeron intercept a,> aoc (Capella andKaplan 1974, Capella et a1 1975) even allowing for uncertainties in the theoretical value of cyoc (Moshe 1978), though ultimately utot will rise as In2s. Fits to the collider data along these lines have been presented by Pajares et a1 (1983) and Capella (1985).…”

“…In other approaches, such as the quark recombination model (Goldberg 1972, Ochs 1977, Das and Hwa 1977, Van Hove 1979 and the quark fragmentation model (Capella et a1 1979, Capella 1981, Cohen-Tannoudji et a1 1979) a more phenomenological approach is taken in which although the language of the quark-parton model is used the dynamics assumed owe very little to QCD but are based on dimensional counting rules (Matveev et a1 1973, Brodsky andFarrar 1973), the quark-parton model and Regge theory. They are reviewed in detail by Fialkowski and Kittel (1983) and the difficulties of interpreting them in terms of perturbative QCD discussed by Gunion (1981).…”