Strings and ropes in heavy-ion collisions: towards a semiclassical unified string-flux tube model

Abstract

The authors review the various string models proposed to describe hadrons and their interactions. QCD and QCD-inspired phenomenological models motivated the development of a rather large variety of string models. Among others the Polyakov model, the Friedberg-Lee model, the MIT flux tube model, semirelativistic string models of hadrons and massive strings are discussed in detail. To correctly describe the dynamical aspects of the hadron-hadron interaction, especially of high-energy heavy-ion collisions, ideas from these models are proposed to be combined into a semiclassical unified string-flux tube model. Special emphasis is given to the dynamical string model recently developed on the basis of such a unified string-flux tube model.

Flux-tube ring and glueball properties in the dual Ginzburg-Landau theory

“…As we can confirm, the phase of the monopole field f = nθ leads the differential form of the flux quantization condition, 26) where the delta functions characterize the center of the flux-tube. Thus, an essential point for the formation of the flux-tube is that the phase of the monopole field becomes singular at the center of the color-electric flux.…”

“…The DGL parameters are determined so as to reproduce the string tension σ ≃ 1 GeV/fm extracted from the Regge slope of the hadrons [26].…”

Aspects of thermal and chemical equilibration of hadronic matter

“…In contrast, our string model does not include energetic string-string interactions that might produce more massive strings. (There exist some phenomenological recipes how to incorporate such interactions [31].) The 'high mass' strings decay to hadrons and, because of the detailed balance problem discussed in the last subsection, are only repopulated by binary hadron-hadron or hadron-string interactions, so that their internal energy is limited and the low-energy hadronic degrees of freedom are overpopulated.…”

Nucleus-nucleus collisions in the dynamical string model

“…There are experimental evidences that hadrons have string like collective degrees of freedom: (i) the well-known, almost linear Regge-trajectories [22] corresponding to the string tension of κ ≈ 0.9 GeV/fm, (ii) the nearly exponential mass spectrum of the resolved hadron resonances [23]; (iii) the existence of a preferred (longitudinal) direction in elementary fragmentation processes; (iv) the emission of linearly polarized gluons by the excited hadronic system occurring in high-energy pp collisions [24]. Theoretical indications and successful applications of the string model for hadronic physics are overviewed in [25]. For our work the success of the string fragmentation models developed by Artru and Mennessier [26] and by the Lund group [6] Energy and momentum conservations are strictly satisfied in any elementary decay and collision event and in the evolution of the whole hadronic system, as well.…”