# Towards an extraction of $\hat{q}$ with an uncertainty controlled energy loss Monte-Carlo

## TL;DR

This paper enhances the LIDO transport model for heavy quarks in quark-gluon plasma, improving physical accuracy and flexibility, enabling better extraction of transport coefficients from experimental data.

## Contribution

The authors introduce key improvements to the LIDO model, including a unified treatment of scattering processes and an advanced implementation of the Landau-Pomeranchuk-Migdal effect, bridging pQCD and Langevin approaches.

## Key findings

- Model now interpolates between pQCD and Langevin approaches.
- Radiative energy loss matches semi-analytic calculations.
- Enhanced Monte-Carlo implementation of gluon scatterings.

## Abstract

Recent progress in open-heavy-flavor measurements and future experimental upgrades are bringing heavy-flavor physics into the precision era, allowing for strong quantitative constraints on the transport properties of heavy quarks in the quark-gluon plasma. Starting from the LIDO transport model, which combines a matrix-element based linearized-Boltzmann transport and diffusion-based Langevin equation, we have made two essential improvements to increase both the flexibility and physical accuracy of the model. First, we have absorbed the pQCD scatterings with small momentum transfers to the medium into the diffusion part of the LIDO model, and we have restricted the use of vacuum matrix elements to large momentum transfer processes. This study allows us to construct a model that smoothly interpolates between a pure pQCD based approach and a radiation-improved Langevin equation by tuning a single scale parameter. Second, the Monte-Carlo implementation of the Landau-Pomeranchuk-Migdal effect of the original model has been improved to account for multiple scatterings of gluons. The simulated radiative energy loss can be tuned to quantitatively agree with semi-analytic theory calculations both for a static (finite / infinite) medium and for a dynamic expanding medium. With such improvements, the LIDO model will greatly facilitate the extraction of heavy-quark transport coefficient from a systematic model-to-data comparison.