Dynamical string-parton model for relativistic heavy-ion collisions

We introduce a dynamical model for the description of hadron-hadron collisions at relativistic energies. The model is based on classical Nambu-Gotō strings. The string motion is performed in unrestricted four-dimensional space-time. The string end points are interpreted as partons which carry energy and momentum. We study ${\mathit{e}}^{+}$ ${\mathit{e}}^{\mathrm{-}}$, e-p, and p-p collisions at various center-of-mass energies. The three basic features of our model are as follows. An ensemble of strings with different end-point dynamics is used to approximately reproduce the valence quark structure functions. We introduce an adiabatic hadronization mechanism for string breakup via qq¯ pair production. The interaction between strings is formulated in terms of a quark-quark scattering amplitude and exchange.