Pion and kaon structure at the electron-ion collider
Pion and kaon structure at the electron-ion collider
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DOI：
10.1140/epja/i2019-12885-0
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发表时间：
2019-07
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影响因子：
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通讯作者：
A. C. Aguilar;Zafir Ahmed;C. Aidala;Salina Ali;V. Andrieux;J. Arrington;A. Bashir;V. Berdnikov-
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文献类型：
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作者：
A. C. Aguilar;Zafir Ahmed;C. Aidala;Salina Ali;V. Andrieux;J. Arrington;A. Bashir;V. Berdnikov-
了解强子结构的起源和动力学，进而了解原子核的起源和动力学是核物理的中心目标。这一挑战带来了这样的问题：表征原子核的大约1GeV质量尺度是如何出现的；为什么它有观察值；以及，令人费解的是，为什么量子色动力学(QCD)中的复合Nambu-Goldstone(NG)玻色子相比之下是反常的轻？从这一角度出发，我们分析了质子和介子在QCD中的质量平衡；讨论了介子的特殊作用，它位于强势和希格斯质量产生机制之间的边界附近；并解释了在QCD唯象和连续介质计算、格子QCD提供的大尺度计算以及在理解强子质量的起源和质量在其中的分布方面取得进展的必要性。我们比较了在电子-离子对撞机(EIC)和强子-电子环加速器(HERA)上预见的独特能力，强子-电子环加速器(HERA)是之前唯一的电子-质子对撞机；并描述了五项关键的实验测量，这些测量由EIC实现，旨在提供基本的见解，将产生具体答案，以解决如何在标准模型的NG模式中产生质量和结构的问题，它们惊人的低质量对我们宇宙的演化至关重要。
Understanding the origin and dynamics of hadron structure and in turn that of atomic nuclei is a central goal of nuclear physics. This challenge entails the questions of how does the roughly 1GeV mass-scale that characterizes atomic nuclei appear; why does it have the observed value; and, enigmatically, why are the composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD) abnormally light in comparison? In this perspective, we provide an analysis of the mass budget of the pion and proton in QCD; discuss the special role of the kaon, which lies near the boundary between dominance of strong and Higgs mass-generation mechanisms; and explain the need for a coherent effort in QCD phenomenology and continuum calculations, in exa-scale computing as provided by lattice QCD, and in experiments to make progress in understanding the origins of hadron masses and the distribution of that mass within them. We compare the unique capabilities foreseen at the electron-ion collider (EIC) with those at the hadron-electron ring accelerator (HERA), the only previous electron-proton collider; and describe five key experimental measurements, enabled by the EIC and aimed at delivering fundamental insights that will generate concrete answers to the questions of how mass and structure arise in the pion and kaon, the Standard Model's NG modes, whose surprisingly low mass is critical to the evolution of our Universe.