A multistage framework for studying the evolution of jets and high-$p_T$ probes in small collision systems

TL;DR

This paper introduces a multistage hybrid framework that models the evolution of jets and high-$p_T$ probes in small collision systems by integrating soft and hard physics, enabling detailed correlation studies.

Contribution

The work extends the JETSCAPE framework to include correlations between soft and hard particles in small systems, combining initial-state showering with hydrodynamics and transport.

Findings

Calibrated the model with $p_T$ spectra in $p$-$p$ collisions.

Compared model predictions with $p$-$Pb$ collision data from LHC.

Analyzed event activity distributions related to jet $p_T$.

Abstract

Understanding the modification of jets and high-$p_T$ probes in small systems requires the integration of soft and hard physics. We present recent developments in extending the JETSCAPE framework to build an event generator, which includes correlations between soft and hard partons, to study jet observables in small systems. The multi-scale physics of the collision is separated into different stages. Hard scatterings are first sampled at binary collision positions provided by the Glauber geometry. They are then propagated backward in space-time following an initial-state shower to obtain the initiating partons' energies and momenta before the collision. These energies and momenta are then subtracted from the incoming colliding nucleons for soft-particle production, modeled by the 3D-Glauber + hydrodynamics + hadronic transport framework. This new hybrid approach (X-SCAPE) includes non-trivial correlations between jet and soft particle productions in small systems. We calibrate this framework with the final state hadrons' $p_T$-spectra from low to high $p_T$ in $p$-$p$, and and then compare with the spectra in $p$-$Pb$ collisions from the LHC. We also present results for additional observables such as the distributions of event activity as a function of the hardest jet $p_T$ in forward and mid-rapidity for both $p$-$p$ and $p$-$Pb$ collisions.