The impact of inclusive electron ion collider data on the strong coupling determination in a global PDF fit

TL;DR

This study assesses how data from the future Electron Ion Collider could influence the precision of the strong coupling constant determination in global parton distribution function fits, highlighting potential impacts and uncertainties.

Contribution

It introduces a framework for evaluating EIC data impact on strong coupling and explores effects of data tensions and uncertainties in the global fit.

Findings

EIC data can significantly improve strong coupling precision under optimistic scenarios.

Conservative assumptions lead to moderate but meaningful impact on the coupling determination.

Data tensions can bias the results, emphasizing the need for comprehensive uncertainty treatment.

Abstract

We present a study of the impact of data from the upcoming Electron Ion Collider (EIC) on the determination of the strong coupling within the context of the global MSHT fitting framework. To achieve this, we generate EIC electron-proton scattering pseudodata according to both conservative and optimistic experimental uncertainty projections and perform a simultaneous fit to obtain the proton PDFs and the value of the strong coupling. In the conservative case the impact is found to be moderate, but non-negligible, while in the optimistic case it is observed to be rather significant. These results therefore underline the promising potential for the EIC in the determination of the strong coupling. We in addition explore the impact of any potential tensions between the EIC data and the rest of the data in the global fit by injecting explicit inconsistencies into the pseudodata generation. This can lead to a noticeable bias in the extracted value of the strong coupling, highlighting the importance of accounting for all sources of theoretical uncertainty in the fit as well as the relevance of an enlarged, conservative, error definition in the determination of the strong coupling.