dorsal/arxiv
View Schema$\sigma$ meson exchange effect on nonmesonic hypernuclear weak decay observables
| Authors | C. Barbero, A. Mariano |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0509037 |
| URL | https://arxiv.org/abs/nucl-th/0509037 |
| DOI | 10.1103/PhysRevC.73.024309 |
| Journal | Phys.Rev.C73:024309,2006 |
Abstract
We analyze the influence of $\sigma$ meson exchange on the main nonmesonic hypernuclear weak decay observables: the total rate, $\Gamma_{NM}$, the neutron-to-proton branching ratio, $\Gamma_{n/p}$, and the proton asymmetry parameter, $a_\Lambda$. The $\sigma$ meson exchange is added to the standard strangeness-changing weak $\Lambda N\to NN$ transition potential, which includes the exchange of the complete pseudoscalar and vector mesons octet ($\pi$, $\eta$, $K$, $\rho$, $\omega$, $K^*$). Using a shell model formalism, the $\sigma$ meson weak coupling constants are adjusted to reproduce the recent $\Gamma_{NM}$ and $\Gamma_{n/p}$ experimental data for $^5_{\Lambda}He$. Numerical results for the remaining observables of $^5_{\Lambda}He$ and all the observables of $^{12}_{\Lambda}C$ decays are presented. They clearly show that the addition of the $\sigma$ meson, in spite of improving some observables values, is not enough to reproduce simultaneously all the measurements, and the puzzle posed by the experimental data remains unexplained.
{
"annotation_id": "0c878bb3-436a-4a27-8fc1-2512c6d0410c",
"date_created": "2026-03-02T18:00:04.920000Z",
"date_modified": "2026-03-02T18:00:04.920000Z",
"file_hash": "c6943398a5bf129d1ca79d2169901fb3315c714e5f45ffd2bc0a54a501cc1427",
"private": false,
"record": {
"abstract": "We analyze the influence of $\\sigma$ meson exchange on the main nonmesonic\nhypernuclear weak decay observables: the total rate, $\\Gamma_{NM}$, the\nneutron-to-proton branching ratio, $\\Gamma_{n/p}$, and the proton asymmetry\nparameter, $a_\\Lambda$. The $\\sigma$ meson exchange is added to the standard\nstrangeness-changing weak $\\Lambda N\\to NN$ transition potential, which\nincludes the exchange of the complete pseudoscalar and vector mesons octet\n($\\pi$, $\\eta$, $K$, $\\rho$, $\\omega$, $K^*$). Using a shell model formalism,\nthe $\\sigma$ meson weak coupling constants are adjusted to reproduce the recent\n$\\Gamma_{NM}$ and $\\Gamma_{n/p}$ experimental data for $^5_{\\Lambda}He$.\nNumerical results for the remaining observables of $^5_{\\Lambda}He$ and all the\nobservables of $^{12}_{\\Lambda}C$ decays are presented. They clearly show that\nthe addition of the $\\sigma$ meson, in spite of improving some observables\nvalues, is not enough to reproduce simultaneously all the measurements, and the\npuzzle posed by the experimental data remains unexplained.",
"arxiv_id": "nucl-th/0509037",
"authors": [
"C. Barbero",
"A. Mariano"
],
"categories": [
"nucl-th"
],
"doi": "10.1103/PhysRevC.73.024309",
"journal_ref": "Phys.Rev.C73:024309,2006",
"title": "$\\sigma$ meson exchange effect on nonmesonic hypernuclear weak decay observables",
"url": "https://arxiv.org/abs/nucl-th/0509037"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "68a144a9-8adf-44ad-aa35-f12c4151c562",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}