No-quenching baseline for energy loss signals in oxygen-oxygen collisions

TL;DR

This paper establishes a baseline for energy loss signals in oxygen-oxygen collisions at RHIC and LHC, highlighting the impact of cold nuclear matter effects and uncertainties in detecting quenching phenomena.

Contribution

It provides a comprehensive no-quenching baseline using advanced theoretical tools, crucial for identifying genuine energy loss in small collision systems.

Findings

Deviations from unity in nuclear modification factors due to cold-nuclear matter effects.

Parton distribution uncertainties hinder energy loss detection in small systems.

Certain kinematic windows reduce uncertainties, aiding energy loss discovery.

Abstract

In this work, we perform computations of inclusive jet, and semi-inclusive jet-hadron cross sections for minimum bias oxygen-oxygen collisions at RHIC and LHC collision energies. We compute the no-quenching baseline for the jet nuclear modification factor $R_\mathrm{AA}$ and jet-, and hadron-triggered semi-inclusive nuclear modification factors $I_\mathrm{AA}$. We do this with state-of-the-art nuclear parton distribution functions (nPDFs), next-to-leading-order matrix elements, parton shower, and hadronization. We observe deviations from unity due to cold-nuclear matter effects, even without quenching. We demonstrate that the parton distribution uncertainties constitute a significant obstacle in detecting energy loss in small collision systems. Hadron-triggered observables are particularly sensitive to uncertainties due to correlations between the trigger and analyzed particles. For jet-triggered $I_\mathrm{AA}$, there exists a kinematic window in which nPDF and scale uncertainties cancel dramatically while showing little sensitivity to parton shower and hadronization models, addressing a major limiting factor for energy loss discovery in small systems.