Soft Limits of Multiparticle Observables and Parton Hadron Duality

TL;DR

This paper explores the behavior of multiparticle production observables in various low-scale limits, demonstrating their smooth transition to perturbative QCD predictions and incorporating mass effects for a comprehensive physical understanding.

Contribution

It introduces a unified analysis of multiparticle observables in different low-scale limits, extending perturbative QCD predictions to include mass effects.

Findings

Observables behave smoothly in low-scale limits

Perturbative QCD predictions remain valid in these limits

Mass effects can be incorporated into the physical picture

Abstract

We discuss observables in multiparticle production for three kinds of limits of decreasing kinematical scales: 1. the transition jet \to hadron (limit y_{cut}\to 0 of the resolution parameter y_{cut}); 2. single particle inclusive distributions normalized at threshold \sqrt s\to 0 and 3. particle densities in the limit of low momentum p,p_T\to 0. The observables show a smooth behaviour in these limits and follow the perturbative QCD predictions, originally designed for large scales, whereby a simple prescription is supplemented to take into account mass effects. A corresponding physical picture is described.