Multi-neutron correlations in light nuclei via ab-initio lattice simulations
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| Format: | Preprint |
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2025
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| _version_ | 1866911458045984768 |
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| author | Zhang, Shuang Elhatisari, Serdar Meißner, Ulf-G. |
| author_facet | Zhang, Shuang Elhatisari, Serdar Meißner, Ulf-G. |
| contents | The quest to understand multi-neutron systems has a long history, and recent experimental efforts aim to probe candidate four-neutron configurations in neutron-rich light nuclei such as ${}^8$He and ${}^7$H via quasi-free knockout reactions. However, the ground-state energies of the hydrogen isotopes ${}^6$H and ${}^7$H are not yet well constrained, with substantial discrepancies across experimental analyses and theoretical predictions. Using ab initio nuclear lattice effective field theory with an ensemble of 282 chiral two- and three-nucleon forces, we perform a Bayesian uncertainty-quantified analysis of the ground-state energies of ${}^6$H and ${}^7$H. The marginal posteriors suggest single-neutron separation energy $S_n({}^{7}\mathrm{H})=0.35^{+0.32}_{-0.32}$ MeV, which kinematically disfavors sequential decay via ${}^{6}\mathrm{H}+n$ and thereby makes multi-neutron emission channels comparatively more relevant. Intrinsic densities indicate triton- and $α$-like clusters in ${}^7$H and ${}^8$He, respectively. By computing two-body and reduced four-body correlation functions, we find that the valence neutrons in the surface region of these systems form compact dineutrons that predominantly organize into approximately symmetric dineutron-dineutron configurations, with only a small but non-negligible fraction assembling into more compact tetraneutron-like substructures. In ${}^7$H, these components account for roughly 95\% and 5\% of the sampled four-neutron configurations, respectively, and ${}^8$He exhibits a similar hierarchy. For these configurations, we also extract the corresponding spatial and angular correlation patterns among the nucleons. These results provide nuclear-structure insights into the debate surrounding four-neutron clusters and complement ongoing experimental searches for tetraneutron signatures in light nuclei. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2512_18849 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Multi-neutron correlations in light nuclei via ab-initio lattice simulations Zhang, Shuang Elhatisari, Serdar Meißner, Ulf-G. Nuclear Theory High Energy Physics - Lattice High Energy Physics - Phenomenology Nuclear Experiment The quest to understand multi-neutron systems has a long history, and recent experimental efforts aim to probe candidate four-neutron configurations in neutron-rich light nuclei such as ${}^8$He and ${}^7$H via quasi-free knockout reactions. However, the ground-state energies of the hydrogen isotopes ${}^6$H and ${}^7$H are not yet well constrained, with substantial discrepancies across experimental analyses and theoretical predictions. Using ab initio nuclear lattice effective field theory with an ensemble of 282 chiral two- and three-nucleon forces, we perform a Bayesian uncertainty-quantified analysis of the ground-state energies of ${}^6$H and ${}^7$H. The marginal posteriors suggest single-neutron separation energy $S_n({}^{7}\mathrm{H})=0.35^{+0.32}_{-0.32}$ MeV, which kinematically disfavors sequential decay via ${}^{6}\mathrm{H}+n$ and thereby makes multi-neutron emission channels comparatively more relevant. Intrinsic densities indicate triton- and $α$-like clusters in ${}^7$H and ${}^8$He, respectively. By computing two-body and reduced four-body correlation functions, we find that the valence neutrons in the surface region of these systems form compact dineutrons that predominantly organize into approximately symmetric dineutron-dineutron configurations, with only a small but non-negligible fraction assembling into more compact tetraneutron-like substructures. In ${}^7$H, these components account for roughly 95\% and 5\% of the sampled four-neutron configurations, respectively, and ${}^8$He exhibits a similar hierarchy. For these configurations, we also extract the corresponding spatial and angular correlation patterns among the nucleons. These results provide nuclear-structure insights into the debate surrounding four-neutron clusters and complement ongoing experimental searches for tetraneutron signatures in light nuclei. |
| title | Multi-neutron correlations in light nuclei via ab-initio lattice simulations |
| topic | Nuclear Theory High Energy Physics - Lattice High Energy Physics - Phenomenology Nuclear Experiment |
| url | https://arxiv.org/abs/2512.18849 |