Monte Carlo Simulations for Polarized and In-medium Parton Evolution in the Nuclear Realm

Andreas Papaefstathiou, Kennesaw State University (Principal Investigator)
Yang-Ting Chien, Georgia State University (Co-Investigator)

Understanding the fundamental components of nuclear matter - the quarks and the gluons - is a central question of nuclear physics. This project aims to deepen that understanding by developing, and applying in detailed phenomenological studies, advanced simulation tools that will allow us to investigate the nuclear realm at particle colliders. Through Monte Carlo (MC) simulations, the project will provide insights into how nuclear constituents behave when polarized, and in extreme conditions. This will illuminate how protons and neutrons are formed through the confinement of quarks and gluons, and how their spin is distributed among these constituents. 

The project's main objectives are:

1. Simulating electron-proton collisions with the effects of spin: We will develop MC tools to simulate interactions where electrons collide with protons, both having their spins aligned in specific directions. This will be essential in clarifying the inner spin structure of protons.

2. Electron-ion collisions probing nuclear structure:  Extending our MC, we will simulate collisions between electrons and a range of nuclei (from light elements like deuterium to heavier ions). This will allow exploration of how quarks and gluons interact with the dense environment of nuclei, providing a new level of understanding on the forces that bind nuclear matter.

3. Modeling jet evolution within a nuclear medium: We will simulate the behavior of jets - streams of particles produced in high-energy collisions - as they traverse through the dense nuclear environment in which they are produced. Studying these interactions will provide insights into a unique state of matter called the quark-gluon plasma, believed to resemble conditions shortly after the Bing Bang.

To achieve these goals, the project leverages HERWIG, a powerful and flexible MC simulation framework. By incorporating new features in HERWIG for handling particle spin and complex nuclear interactions, the simulations will reach a precision level critical for upcoming collider experiments, such as the planned Electron-Ion Collider (EIC) at the Brookhaven National Lab. These simulations will directly support experimental programs, enabling scientists to interpret experimental data, and guiding the next generation of measurements. The findings of this endeavor could offer unprecedented insights into nuclear interactions. The partnership between Kennesaw State University and Georgia State University will foster a collaborative, inclusive research environment, positioning both institutions as leaders in theoretical nuclear physics.