# Introducing HIJING++: the Heavy Ion Monte Carlo Generator for the High-Luminosity LHC Era

## TL;DR

HIJING++ is a modern, high-performance Monte Carlo generator designed to replace the legacy FORTRAN HIJING, supporting advanced simulation needs for the High-Luminosity LHC era with enhanced flexibility and analysis capabilities.

## Contribution

It introduces HIJING++, a new C++ based Monte Carlo generator with improved modularity, analysis interface, and compatibility with modern data formats, building upon the original HIJING.

## Key findings

- Pre-release results agree with proton-proton experimental data.
- HIJING++ shows comparable or improved performance over Pythia8.
- The generator supports multiple event data formats and analysis tools.

## Abstract

Beyond 2025 we will enter the High-Luminosity era of the LHC, right after the upgrades of the third Long Shutdown of the Large Hadron Collider (LHC). The ongoing state-of-the-art experimental instrument upgrades require high-performance simulation support in the background, that is modern, robust, and comes with long term support. The original FORTRAN based HIJING (Heavy Ion Jet INteraction Generator) has been used intensively since almost three decades by the high energy physics and heavy-ion community. However, it is getting overly challenging to conform to these new requirements. Our novel Monte Carlo event generator, the HIJING++ is the successor of the old FORTRAN version containing all the physics that its predecessor have. Moreover, among others a flexible module handling layer and an analysis interface is also introduced. This latter supports the most popular event container formats such as simple ascii, ROOT and the HepMC format, together with RIVET support. In this paper we compare the pre-release results of HIJING++ with proton-proton experimental data and Pythia8 calculations.