Regge-cascade hadronization

Abstract

We argue that the evolution of coloured partons into colour-singlet hadrons has approximate factorization into an extended parton-shower phase and a colour-singlet resonance--pole phase. The amplitude for the conversion of colour connected partons into hadrons necessarily resembles Regge-pole amplitudes since qq-bar resonance amplitudes and Regge-pole amplitudes are related by duality. A `Regge-cascade' factorization property of the N-point Veneziano amplitude provides further justification of this protocol. This latter factorization property, in turn, allows the construction of general multi-hadron amplitudes in amplitude-squared factorized form from (1->2) link amplitudes. We suggest an algorithm with cascade-decay configuration, ordered in the transverse momentum, suitable for Monte-Carlo simulation. We make a simple implementation of this procedure in Herwig++, obtaining some improvement to the description of the event-shape distributions at LEP.