Transverse momentum correlations of quarks in recursive jet models

TL;DR

This paper introduces a new string fragmentation model that incorporates transverse momentum correlations of quarks, challenging the uncorrelated assumption in PYTHIA and aligning with theoretical expectations.

Contribution

It proposes a simple, new recipe for string fragmentation that naturally includes transverse momentum correlations, improving the realism of jet simulations.

Findings

The new model predicts correlated transverse momenta in quark jets.

It discusses the impact of jet axis definition on transverse momentum.

The approach aligns with covariant multiperipheral models.

Abstract

In the symmetric string fragmentation recipe adopted by PYTHIA for jet simulations, the transverse momenta of successive quarks are uncorrelated. This is a simplification but has no theoretical reason. Transverse momentum correlations are naturally expected, for instance, in a covariant multiperipheral model of quark hadronization. We propose a simple recipe of string fragmentation which lead to such correlations. The definition of the jet axis and its relation with the primordial transverse momentum of the quark is also discussed.