Eur. Phys. J. Spec. Top.
https://doi.org/10.1140/epjs/s11734-026-02227-9

Review

Nucleon short-range correlations and high-momentum dynamics: implications on the equation of state of dense matter

¹ Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, 200433, Shanghai, China
² Shanghai Research Center for Theoretical Nuclear Physics, NSFC and Fudan University, 200438, Shanghai, China
³ Department of Physics and Astronomy, East Texas A&M University, 75429-3011, Commerce, TX, USA
⁴ College of Physics, East China Normal University, 200241, Shanghai, China

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Received: 3 December 2025
Accepted: 17 February 2026
Published online: 19 March 2026

Abstract

Nucleon short-range correlations (SRCs) and their associated high-momentum tails (HMTs) in the single-nucleon momentum distribution $n_{\mathbf{k}}=n(k)$ have emerged as key manifestations of strong, short-range dynamics in nuclear many-body systems. Despite substantial recent progress, our understanding of these correlations and their implications for finite nuclei, nuclear reactions, and dense matter remains incomplete and continues to evolve. In this review, we offer a necessarily selective overview of several aspects of SRC physics that directly influence the equation of state (EOS) of dense matter, particularly in regimes of large isospin asymmetry and high baryon density. We first summarize the empirical and theoretical features of the momentum distribution $n_{\mathbf{k}}=n(k)$, including its isospin dependence, microscopic origins, and representative parameterizations. Special emphasis is placed on the strong neutron–proton (np) tensor force at intermediate momenta, which drives the dominance of correlated np pairs and enhances the minority-species HMT in asymmetric nuclei and nuclear matter. We further discuss connections to nucleon effective masses, quasi-deuteron components, and orbital entanglement entropy, providing a broader microscopic foundation that links SRCs to single-particle and two-body structure. We then examine how SRC-induced HMTs modify the EOS of asymmetric nuclear matter within both non-relativistic and relativistic frameworks. The depletion of low-momentum states and the repopulation of high-momentum components alter kinetic and potential contributions to the EOS. We additionally consider generalizations to arbitrary spatial dimensions and estimates involving very high-momentum components, which help clarify the sensitivity of the EOS to the detailed structure of n(k). Particular attention is devoted to the softening of the kinetic symmetry energy and to deviations from the standard parabolic approximation of isospin-asymmetric nuclear-matter EOS, effects that grow increasingly important with isospin asymmetry. In the context of heavy-ion reactions, we summarize the influence of SRCs on isospin-sensitive observables including particle yields, nuclear collective flows, and neutron–proton bremsstrahlung gamma rays. These effects arise from both modified initial momentum distributions and the increased availability of high relative-momentum np pairs, which can strongly affect threshold behavior and transport dynamics. We also briefly comment on experimental probes of high-momentum nucleon components, including electron- and proton-induced knockout reactions and meson production channels in heavy-ion reactions. Finally, we discuss implications for neutron-star matter, wherein extreme densities and large isospin asymmetries amplify many SRC-induced effects known from finite nuclei. Topics include consequences for mass–radius relations, tidal deformabilities, proton fractions, Migdal–Luttinger Z-factors, cooling processes, and the core–crust transition. We also highlight potential connections between SRC-modified nucleon momentum distributions and dark-matter interactions in dense astrophysical environments.