A Brief Introduction to PACIAE 4.0

TL;DR

PACIAE 4.0 is a modernized, C++-based Monte Carlo event generator for simulating a wide range of high-energy collision processes, improving upon previous versions with enhanced physics modeling.

Contribution

It introduces a C++ implementation of PACIAE, integrating PYTHIA 8.3, and adds new features to better simulate high-energy collision phenomena.

Findings

Refactored code from FORTRAN to C++ for better flexibility.

Integrated PYTHIA 8.3 for improved event generation.

Enhanced physics features for more accurate collision modeling.

Abstract

Parton And-hadron China Institute of Atomic Energy (PACIAE) is a multipurpose Monte Carlo event generator developed to describe a wide range of high-energy collisions, including lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions. It is built based on the PYTHIA program, and incorporates parton and hadron cascades to address the nuclear medium effects. PACIAE 4.0 is the new generation of PACIAE model surpassing the version 3.0. In PACIAE 4.0, the old fixed-format FORTRAN 77 code has been refactored and rewritten by the free-format modern Fortran and C++ languages. The C++-based PYTHIA 8.3 is interfaced in, while previous versions connected to the Fortran-based PYTHIA 6.4 only. Several improvements are also introduced, which enable PACIAE 4.0 to contain more physics and features to model the high-energy collisions. This is the first attempt to transition PACIAE from Fortran to C++.