[论文解读] Inclusive electron-proton measurement prospects in the Electron-Ion Collider early science stage

Javier Jiménez-López, Stephen Maple+2 more|arXiv (Cornell University)|Jan 31, 2026

Particle physics theoretical and experimental studies被引用 0

一句话总结

该论文评估在早期 EIC 下，通过 inclusive DIS 的 Rosenbluth 分离，单独或结合 HERA 数据，如何提取质子结构函数 F2 和 FL、PDFs 以及 αs(MZ^2)，并评估两种与三种束能配置的影响。

ABSTRACT

We explore the potential for extracting proton structure functions, proton parton density functions (PDFs), and the strong coupling $α_s(M_z^2)$, using early science data from the future Electron-Ion Collider (EIC), both standalone, and in combination with HERA data. Different scenarios are considered in which samples with modest luminosity are collected at either two or three EIC beam energy configurations. The Rosenbluth separation method is used to extract the proton structure functions $F_2$ and $F_L$ from simulated data in a model-independent manner, showing that $F_L$ can be extracted significantly more precisely with three centre of mass energies than with two, whilst also obtaining $F_2$ to higher precision than has been achieved previously. The inclusion of a third beam configuration is also beneficial in the extraction of the strong coupling $α_s(M_z^2)$ that is obtainable with unprecedented experimental precision with the early EIC data. Additionally, the precision of the proton PDFs is improved when adding these data, especially for large values of Bjorken-$x$, for both two and three EIC beam energy configurations. These studies show that EIC data will already be a highly competitive probe of perturbative Quantum Chromodynamics within the first five years of data taking.

研究动机与目标

• Motivate precision measurements of proton structure via inclusive DIS at the EIC during the first five years.
• Evaluate model-independent extraction of F2 and FL using Rosenbluth separation with simulated EIC pseudo-data.
• Assess improvements to proton PDFs and the strong coupling αs(MZ^2) from early EIC data, with and without HERA data.
• Investigate the benefits of adding a third EIC beam-energy configuration for early science.
• Explore alternative scenarios including luminosity and systematic variations on the extraction outcomes.

提出的方法

• Generate inclusive e-p DIS pseudo-data for two or three EIC center-of-mass energies using baseline EIC configurations and 1 fb−1 luminosity per configuration.
• Extract F2 and FL via Rosenbluth-type fits to σr(x,Q2,y) across multiple s values, using χ2 minimisation and replica averaging to capture uncertainties.
• Combine HERA inclusive cross sections with EIC pseudo-data to perform joint extractions of structure functions, PDFs, and αs within NNLO QCD fits in xFitter/HERAPDF2.0 framework.
• Compare EIC-only and HERA+EIC scenarios, as well as two versus three beam-energy configurations, to quantify lever arms and precision.
• Quantify improvements in αs(MZ^2) from global fits with EIC data, reporting experimental uncertainties and ∆χ2 scans.

实验结果

研究问题

• RQ1 How precisely can F2 and FL be extracted from early-EIC inclusive data using Rosenbluth separation across two or three center-of-mass energies?
• RQ2 What is the impact of combining HERA data with EIC early-science data on F2, FL, and the extraction precision of PDFs and αs(MZ^2)?
• RQ3 How does adding a third, lower-energy EIC beam configuration affect the kinematic reach and precision of FL, F2, PDFs, and αs?
• RQ4 What are the expected experimental uncertainties and lever arms for FL and F2 in EIC-only versus HERA+EIC analyses?
• RQ5 How robust are the projected improvements to systematic assumptions and luminosity variations in the early science phase?

主要发现

• F2 和 FL 可以通过 Rosenbluth 分离进行模型无关的测量，且在使用三种束能时 FL 的精确度显著提高。
• 将 EIC 数据与两种束配置结合，相较于仅有 HERA，FL 和 F2 的精度得到提升，尤其是在结合 HERA+EIC 时 FL 的提升更为显著。
• 第三种较低能量的 EIC 配置延长了 y 力臂，在两能量情形中考虑时，FL 的精度有约10–20%的改进。
• 对两种与三种能量配置而言，PDF 不确定度随 EIC 数据而降低，尤其在大 Bjorken x 区域；对 gluon 与上值峡分布有明显收益。
• αs(MZ^2) 可达到世界领先的精度；两能量约为 0.1162(±0.0008)，三能量约为 0.1158(±0.0006)，在实验不确定度范围内。
• 增加第三种能量在约 twenty-five percent 的 αs 不确定度下降，并在不同实验情景下仍提供稳健改进。