Modelling Early-Time Baryon Dynamics in the Fragmentation Region

As forward detector upgrades at RHIC and the LHC prepare to take data, interpreting the dynamics of the fragmentation regions requires theoretical baselines that extend beyond traditional boost-invariant paradigms.

This talk explores a newly developed 3+1D classical transport framework designed to model pre-equilibrium baryon number deposition. Working in the target rest frame, the collision is modelled as an ultra-relativistic Colour Glass Condensate sheet traversing a static distribution of collisionless Wong quarks. We extract the saturation-driven momentum kicks imparted to the target quarks from the McLerran Venugopalan model and establish a kinetic transport framework that is robust enough to accommodate and arbitrary initial distribution, including a Woods-Saxon profile.

The presentation will focus on preliminary results that demonstrate the competition between longitudinal compression and transverse expansion induced by momentum broadening. These findings lay the mathematical groundwork for a macroscopic baseline for forward-rapidity hydrodynamics.