Average formation length in string model

TL;DR

This paper investigates the space-time scales of hadronization in the string model, showing that average formation lengths of pseudoscalar mesons depend on charge, target, and kinematic variables, with implications for nuclear hadronization understanding.

Contribution

It provides a detailed analysis of formation lengths in the string model, including charge dependence and effects of resonance decay, which is a novel insight into hadronization processes.

Findings

Positively charged mesons have larger formation lengths than negatively charged ones.

Including resonance decay reduces the average formation lengths.

Formation lengths vary slowly with Bjorken x, increasing for positive and decreasing for negative mesons.

Abstract

The space-time scales of the hadronization process in the framework of string model are investigated. It is shown that the average formation lengths of pseudoscalar mesons, produced in semi-inclusive deep inelastic scattering (DIS) of leptons on different targets, depend from their electrical charges. In particular the average formation lengths of positively charged hadrons are larger than of negatively charged ones. This statement is fulfiled for all using scaling functions, for $z$ (the fraction of the virtual photon energy transferred to the detected hadron) larger than 0.15, for all nuclear targets and any value of the Bjorken scaling variable $x_{Bj}$. In all cases, the main mechanism is direct production of pseudoscalar mesons. Including in consideration additional mechanism of production in result of decay of resonances, leads to decrease of average formation lengths. It is shown that the average formation lengths of positively (negatively) charged mesons are slowly rising (decreasing) functions of $x_{Bj}$. The obtained results can be important, in particular, for the understanding of the hadronization process in nuclear environment.