Impact of neutron-proton pairing on the nucleon high-momentum distribution in symmetric nuclear matter

Fuente: arXiv
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Main Authors: Li, Guo-peng, Fu, Ji-you, Zhou, Jin, Shang, Xin-le, Dong, Jian-min, Zuo, Wei
Format: Preprint
Published: 2026
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author Li, Guo-peng
Fu, Ji-you
Zhou, Jin
Shang, Xin-le
Dong, Jian-min
Zuo, Wei
author_facet Li, Guo-peng
Fu, Ji-you
Zhou, Jin
Shang, Xin-le
Dong, Jian-min
Zuo, Wei
contents The effect of neutron-proton ($np$) pairing on the high-momentum tail (HMT) of nucleon momentum distributions in symmetric nuclear matter is investigated within a combined framework of the extended Brueckner-Hartree-Fock approach with off-shell BCS theory. The HMT ratio, quantifying the high-momentum fraction in the BCS state relative to the normal state, reaches about $1.06$ around the density of $0.052\ \mathrm{fm}^{-3}$, indicating that the maximal contribution of the $np$ pairing, amounts to approximately 6\% that from short-range correlations (SRCs). This contribution exhibits a density dependence that closely follows the squared relative pairing gap $\widetildeΔ_F=Z_FΔ(k_F)$ with respect to the kinetic energy $E_{k_F}^*$ evaluated using the effective mass, suggesting that $\widetildeΔ_F^2/E_{k_F}^{*2}$ provides a qualitative measure of the $np$ pairing effect on the HMT. These findings highlight the significant role of $np$ pairing and its interplay with SRCs in shaping nucleon momentum distributions in nuclear matter.
format Preprint
id arxiv_https___arxiv_org_abs_2604_05410
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Impact of neutron-proton pairing on the nucleon high-momentum distribution in symmetric nuclear matter
Li, Guo-peng
Fu, Ji-you
Zhou, Jin
Shang, Xin-le
Dong, Jian-min
Zuo, Wei
Nuclear Theory
The effect of neutron-proton ($np$) pairing on the high-momentum tail (HMT) of nucleon momentum distributions in symmetric nuclear matter is investigated within a combined framework of the extended Brueckner-Hartree-Fock approach with off-shell BCS theory. The HMT ratio, quantifying the high-momentum fraction in the BCS state relative to the normal state, reaches about $1.06$ around the density of $0.052\ \mathrm{fm}^{-3}$, indicating that the maximal contribution of the $np$ pairing, amounts to approximately 6\% that from short-range correlations (SRCs). This contribution exhibits a density dependence that closely follows the squared relative pairing gap $\widetildeΔ_F=Z_FΔ(k_F)$ with respect to the kinetic energy $E_{k_F}^*$ evaluated using the effective mass, suggesting that $\widetildeΔ_F^2/E_{k_F}^{*2}$ provides a qualitative measure of the $np$ pairing effect on the HMT. These findings highlight the significant role of $np$ pairing and its interplay with SRCs in shaping nucleon momentum distributions in nuclear matter.
title Impact of neutron-proton pairing on the nucleon high-momentum distribution in symmetric nuclear matter
topic Nuclear Theory
url https://arxiv.org/abs/2604.05410