Hyperonic Softening versus Nucleonic Three-Body Repulsion in Hypernuclear Matter within a microscopic approach
Abstract
We investigate cold homogeneous matter composed of neutrons, protons, and Λ hyperons within our hyperonic extension of the lowest-order constrained variational (LOCV) method, hereafter denoted LOCVY. Our earlier LOCVY calculation, based on two-baryon interactions, is extended by supplementing the Argonne v18 nucleonic interaction with the Urbana IX three-nucleon force, reduced within the variational framework to a correlation-weighted density-dependent effective two-nucleon interaction. The NΛ and ΛΛ interactions are kept unchanged, allowing the present calculation to isolate the competition between hyperon-induced softening and nucleonic three-body repulsion. The energy per baryon is calculated for fixed Λ fractions YΛ=0, $0.1$, and $0.2$ in matter with a symmetric nucleonic component and in the proton-free neutron--Λ limit. Direct differences between calculations with and without the three-body force quantify its density-dependent contribution, while a complementary decomposition into NN, NΛ, and ΛΛ terms identifies the microscopic origin of the stiffening. The Urbana contribution becomes increasingly repulsive with density and opposes, but does not generically remove, the softening associated with a finite Λ content. We further investigate the saturation properties for several prescribed Λ fractions, with and without the nucleonic three-body force, to clarify how strangeness and many-body interactions modify the saturation point and the agreement with empirical nuclear-matter properties.
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BibTeX
@misc{shahrbaf2026hyperonic,
title = {{Hyperonic Softening versus Nucleonic Three-Body Repulsion in Hypernuclear Matter within a microscopic approach}},
author = {Mahboubeh Shahrbaf},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.00851},
eprint = {2609.00851},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.00851},
}
RIS
TY - UNPB
TI - Hyperonic Softening versus Nucleonic Three-Body Repulsion in Hypernuclear Matter within a microscopic approach
AU - Mahboubeh Shahrbaf
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2609.00851
UR - https://arxiv.org/abs/2609.00851
AB - We investigate cold homogeneous matter composed of neutrons, protons, and Λ hyperons within our hyperonic extension of the lowest-order constrained variational (LOCV) method, hereafter denoted LOCVY. Our earlier LOCVY calculation, based on two-baryon interactions, is extended by supplementing the Argonne v_18 nucleonic interaction with the Urbana IX three-nucleon force, reduced within the variational framework to a correlation-weighted density-dependent effective two-nucleon interaction. The NΛ and ΛΛ interactions are kept unchanged, allowing the present calculation to isolate the competition between hyperon-induced softening and nucleonic three-body repulsion. The energy per baryon is calculated for fixed Λ fractions Y_Λ=0, $0.1$, and $0.2$ in matter with a symmetric nucleonic component and in the proton-free neutron--Λ limit. Direct differences between calculations with and without the three-body force quantify its density-dependent contribution, while a complementary decomposition into NN, NΛ, and ΛΛ terms identifies the microscopic origin of the stiffening. The Urbana contribution becomes increasingly repulsive with density and opposes, but does not generically remove, the softening associated with a finite Λ content. We further investigate the saturation properties for several prescribed Λ fractions, with and without the nucleonic three-body force, to clarify how strangeness and many-body interactions modify the saturation point and the agreement with empirical nuclear-matter properties.
ER -