dorsal/arxiv
View SchemaChiral dynamics of $\Sigma$-hyperons in the nuclear medium
| Authors | N. Kaiser |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0601101 |
| URL | https://arxiv.org/abs/nucl-th/0601101 |
| DOI | 10.1103/PhysRevC.71.068201 |
| Journal | Phys.Rev. C71 (2005) 068201 |
Abstract
Using SU(3) chiral perturbation theory we calculate the density-dependent complex mean field $U_\Sigma(k_f)+ i W_\Sigma(k_f)$ of a $\Sigma$-hyperon in isospin-symmetric nuclear matter. The leading long-range $\Sigma N $-interaction arises from one-kaon exchange and from two-pion exchange with a $\Sigma$- or a $\Lambda$-hyperon in the intermediate state. We find from the $\Sigma N\to \Lambda N$ conversion process at nuclear matter saturation density $\rho_0 = 0.16 $fm$^{-3}$ an imaginary single-particle potential of $W_\Sigma(k_{f0}) =-21.5$ MeV, in fair agreement with existing empirical determinations. The genuine long-range contributions from iterated (second order) one-pion exchange with an intermediate $\Sigma$- or $\Lambda$-hyperon sum up to a moderately repulsive real single-particle potential of $U_\Sigma(k_{f0})= 59$ MeV. Recently measured $(\pi^-,K^+$) inclusive spectra related to $\Sigma^-$-formation in heavy nuclei give evidence for a $\Sigma$-nucleus repulsion of similar size. Our results suggest that the net effect of the short-range $\Sigma N$-interaction on the $\Sigma$-nuclear mean field could be small.
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"abstract": "Using SU(3) chiral perturbation theory we calculate the density-dependent\ncomplex mean field $U_\\Sigma(k_f)+ i W_\\Sigma(k_f)$ of a $\\Sigma$-hyperon in\nisospin-symmetric nuclear matter. The leading long-range $\\Sigma N\n$-interaction arises from one-kaon exchange and from two-pion exchange with a\n$\\Sigma$- or a $\\Lambda$-hyperon in the intermediate state. We find from the\n$\\Sigma N\\to \\Lambda N$ conversion process at nuclear matter saturation density\n$\\rho_0 = 0.16 $fm$^{-3}$ an imaginary single-particle potential of\n$W_\\Sigma(k_{f0}) =-21.5$ MeV, in fair agreement with existing empirical\ndeterminations. The genuine long-range contributions from iterated (second\norder) one-pion exchange with an intermediate $\\Sigma$- or $\\Lambda$-hyperon\nsum up to a moderately repulsive real single-particle potential of\n$U_\\Sigma(k_{f0})= 59$ MeV. Recently measured $(\\pi^-,K^+$) inclusive spectra\nrelated to $\\Sigma^-$-formation in heavy nuclei give evidence for a\n$\\Sigma$-nucleus repulsion of similar size. Our results suggest that the net\neffect of the short-range $\\Sigma N$-interaction on the $\\Sigma$-nuclear mean\nfield could be small.",
"arxiv_id": "nucl-th/0601101",
"authors": [
"N. Kaiser"
],
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"doi": "10.1103/PhysRevC.71.068201",
"journal_ref": "Phys.Rev. C71 (2005) 068201",
"title": "Chiral dynamics of $\\Sigma$-hyperons in the nuclear medium",
"url": "https://arxiv.org/abs/nucl-th/0601101"
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