The last decade has seen a marked shift in how the internal structure of hadrons is understood. Modern experimental facilities, new theoretical techniques for the continuum bound-state problem and progress with lattice-regularised QCD have provided strong indications that soft quark+quark (diquark) correlations play a crucial role in hadron physics. For example, theory indicates that the appearance of such correlations is a necessary consequence of dynamical chiral symmetry breaking, viz. a corollary of emergent hadronic mass that is responsible for almost all visible mass in the universe; experiment has uncovered signals for such correlations in the flavour-separation of the proton's electromagnetic form factors; and phenomenology suggests that diquark correlations might be critical to the formation of exotic tetra- and penta-quark hadrons. A broad spectrum of such information is evaluated herein, with a view to consolidating the facts and therefrom moving toward a coherent, unified picture of hadron structure and the role that diquark correlations might play.

中文翻译：

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强子物理学中的狄夸克相关性：起源、影响和证据

在过去十年中，人们对强子内部结构的理解发生了显着变化。现代实验设施、连续态束缚态问题的新理论技术以及晶格正则化 QCD 的进展提供了强有力的迹象，表明软夸克+夸克（双夸克）相关性在强子物理学中起着至关重要的作用。例如，理论表明这种相关性的出现是动态手征对称性破坏的必然结果，即。出现的强子质量的必然结果，它负责宇宙中几乎所有可见的质量；实验揭示了质子电磁形状因子的风味分离中这种相关性的信号；现象学表明，双夸克相关性可能对奇异四夸克和五夸克强子的形成至关重要。