First results from Hybrid Hadronization in small and large systems

TL;DR

This paper introduces Hybrid Hadronization, a Monte Carlo package that combines quark recombination and string fragmentation to model hadronization across different collision systems, demonstrating its application with various parton shower generators.

Contribution

The paper presents Hybrid Hadronization, a novel Monte Carlo tool integrating recombination and string fragmentation, compatible with PYTHIA 8 and applicable to diverse collision systems.

Findings

Hybrid Hadronization successfully models hadron chemistry in small and large systems.

Recombination effects influence observable fragmentation functions.

The package is integrated into JETSCAPE for broad accessibility.

Abstract

"Hybrid Hadronization" is a new Monte Carlo package to hadronize systems of partons. It smoothly combines quark recombination applicable when distances between partons in phase space are small, and string fragmentation appropriate for dilute parton systems, following the picture outlined by Han et al. [PRC 93, 045207 (2016)]. Hybrid Hadronization integrates with PYTHIA 8 and can be applied to a variety of systems from $e^++e^-$ to $A+A$ collisions. It takes systems of partons and their color flow information, for example from a Monte Carlo parton shower generator, as input. In addition, if for $A+A$ collisions a thermal background medium is provided, the package allows sampling thermal partons that contribute to hadronization. Hybrid Hadronization is available for use as a standalone code and is also part of JETSCAPE since the 2.0 release. In these proceedings we review the physics concepts underlying Hybrid Hadronization and demonstrate how users can use the code with various parton shower Monte Carlos. We present calculations of hadron chemistry and fragmentation functions in small and large systems when Hybrid Hadronization is combined with parton shower Monte Carlos MATTER and LBT. In particular, we discuss observable effects of the recombination of shower partons with thermal partons.