Energy loss predicts no $v_2$ in small systems
Abstract
We present high- and from a perturbative quantum chromodynamics-based energy loss model that includes event-by-event hydrodynamic evolution of the medium and small system size corrections to the energy loss. The model is calibrated on, and describes well, large system and experimental data. The extrapolation of our model to and agrees quantitatively with recent experimental measurements of . Surprisingly, at high- our energy loss model predicts for all symmetric and asymmetric small systems when extracted using either hard-hard or hard-soft two-particle correlations. We argue that all energy loss models will in general predict when extracted using hard-soft correlations, which is the usual experimental method for measuring anisotropy in hadronic collisions, due to a generic geometric decorrelation between the hard and soft sector participant planes.
Keywords
Cite
@article{arxiv.2603.21861,
title = {Energy loss predicts no $v_2$ in small systems},
author = {Ben Bert and Coleridge Faraday and W. A. Horowitz},
journal= {arXiv preprint arXiv:2603.21861},
year = {2026}
}
Comments
12 pages, 5 figures