[論文レビュー] Snowmass 2021 White Paper: Electron Ion Collider for High Energy Physics

Rabah Abdul Khalek, U. D’Alesio+106 more|arXiv (Cornell University)|Mar 24, 2022

Particle Accelerators and Free-Electron Lasers被引用数 39

ひとこと要約

このSnowmass 2021のホワイトペーパーは、偏極電子–陽子/イオン衝突型の Collision である Electron Ion Collider (EIC) を提案し、標準模型を超える探索からハドロン断層像（トモグラフィー）、ジェット、重いフレーバー、そして小xのQCDに至る物理プログラムを概説します。電弱およびPDF制約の予測も含みます。

ABSTRACT

Electron Ion Collider (EIC) is a particle accelerator facility planned for construction at Brookhaven National Laboratory on Long Island, New York by the United States Department of Energy. EIC will provide capabilities of colliding beams of polarized electrons with polarized beams of proton and light ions. EIC will be one of the largest and most sophisticated new accelerator facilities worldwide, and the only new large-scale accelerator facility planned for construction in the United States in the next few decades. The versatility, resolving power and intensity of EIC will present many new opportunities to address some of the crucial and fundamental open scientific questions in particle physics. This document provides an overview of the science case of EIC from the perspective of the high energy physics community.

研究の動機と目的

• Motivate the EIC as a versatile new US accelerator facility for high-energy and nuclear physics.
• Outline the broad science program including BSM EW physics, hadron/nucleus tomography, jets, heavy flavors, and small-x QCD.
• Highlight how EIC measurements complement LHC/other facilities in probing PDFs, EFT/Wilson coefficients, and flavor structure.
• Provide projections and methodological approaches for extracting fundamental parameters such as sin^2(theta_W) and SMEFT coefficients.

提案手法

• Describe the DIS cross sections with polarization dependence and the relevant structure functions (F2, F3, g1, g5) for gamma, gamma-Z, and Z exchanges.
• Discuss parity-violating asymmetries and their use to extract sin^2(theta_W and polarized PDFs.
• Apply SMEFT framework with dimension-6 four-fermion operators to show how EIC data can constrain Wilson coefficients and resolve flat directions when combined with LHC data.
• Analyze impact on PDFs and flavor decomposition via gamma-Z interference structure functions and their effect on unpolarized and polarized PDFs.
• Present prospects for charged lepton flavor violation searches and collider-based CLFV constraints (e.g., leptoquarks) at the EIC.
• Outline readiness aspects including event generation, detector configurations (ECCЕ), and fast smearing simulations for EW studies.

実験結果

リサーチクエスチョン

• RQ1 How can EIC measurements of parity-violating DIS constrain the weak mixing angle across accessible Q^2 ranges?
• RQ2 What SMEFT operators and Wilson coefficients can be constrained by EIC data, and how does EIC resolve flat directions when combined with LHC data?
• RQ3 How do gamma-Z interference structure functions at the EIC affect unpolarized and polarized PDFs and flavor sensitivity?
• RQ4 What is the potential reach of EIC in probing charged lepton flavor violation and related BSM scenarios (e.g., leptoquarks, ALPs, Lorentz/CPT violation)?
• RQ5 How does EIC complement existing collider data to advance QCD tomography and hadron/nucleus structure?

主な発見

• Projected EIC measurements can determine sin^2(theta_W) with sensitivity bridging high-energy and low-energy tests, using A_PV measurements from ep and eD collisions.
• SMEFT analyses show EIC data significantly reduce flat directions in Wilson coefficient space when combined with LHC Drell-Yan data, improving constraints on 2-lepton/2-quark operators.
• A_PV measurements at the EIC enhance sensitivity to gamma-Z interference and improve flavor separation in PDFs beyond electromagnetic structure functions.
• Parity-violating data at the EIC can substantially impact polarized and unpolarized PDF determinations, notably for strange and light antiquark sectors.
• The EIC’s high luminosity and polarization capabilities enable searches for CLFV and other BSM phenomena (e.g., leptoquarks, heavy photons) in e+p and e+A settings.
• The document presents methodology and projections using fast simulations (Djangoh generator) and detector configurations (ECCЕ) to study EW physics at the EIC.