Hypernuclear weak decay puzzle
- Autores
- Barbero, César Alberto; Horvat, Dubravko; Krmpotić, Francisco; Kuo, T. T. S.; Narančić, Zoran; Tadić, Dubravko
- Año de publicación
- 2002
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γn and Γp, which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K*), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of ¹²ΛC is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate ΓNM = Γn + Γp is of the order of the free Λ decay rate Γ⁰(ΓthNM ≅ Γ⁰) and is consistent with experiments. Yet the measurements of Γn/p = Γn / Γp and of Γp are not well accounted for by the theory (Γthn/p ≲ 0.42,Γthp ≳ 0.60Γ⁰). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified.
Facultad de Ciencias Exactas - Materia
-
Ciencias Exactas
Física
general shell model formalism
nonmesonic weak decay
hypernuclei - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by-nc-sa/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/125943
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Hypernuclear weak decay puzzleBarbero, César AlbertoHorvat, DubravkoKrmpotić, FranciscoKuo, T. T. S.Narančić, ZoranTadić, DubravkoCiencias ExactasFísicageneral shell model formalismnonmesonic weak decayhypernucleiA general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γ<sub>n</sub> and Γ<sub>p</sub>, which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K*), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of ¹²<sub>Λ</sub>C is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate Γ<sub>NM</sub> = Γ<sub>n</sub> + Γ<sub>p</sub> is of the order of the free Λ decay rate Γ⁰(Γ<sup>th</sup><sub>NM</sub> ≅ Γ⁰) and is consistent with experiments. Yet the measurements of Γ<sub>n/p</sub> = Γ<sub>n</sub> / Γ<sub>p</sub> and of Γ<sub>p</sub> are not well accounted for by the theory (Γ<sup>th</sup><sub>n/p</sub> ≲ 0.42,Γ<sup>th</sup><sub>p</sub> ≳ 0.60Γ⁰). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified.Facultad de Ciencias Exactas2002-11info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/125943enginfo:eu-repo/semantics/altIdentifier/issn/0556-2813info:eu-repo/semantics/altIdentifier/issn/1089-490Xinfo:eu-repo/semantics/altIdentifier/arxiv/nucl-th/0011092info:eu-repo/semantics/altIdentifier/doi/10.1103/physrevc.66.055209info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:30:18Zoai:sedici.unlp.edu.ar:10915/125943Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:30:18.369SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Hypernuclear weak decay puzzle |
title |
Hypernuclear weak decay puzzle |
spellingShingle |
Hypernuclear weak decay puzzle Barbero, César Alberto Ciencias Exactas Física general shell model formalism nonmesonic weak decay hypernuclei |
title_short |
Hypernuclear weak decay puzzle |
title_full |
Hypernuclear weak decay puzzle |
title_fullStr |
Hypernuclear weak decay puzzle |
title_full_unstemmed |
Hypernuclear weak decay puzzle |
title_sort |
Hypernuclear weak decay puzzle |
dc.creator.none.fl_str_mv |
Barbero, César Alberto Horvat, Dubravko Krmpotić, Francisco Kuo, T. T. S. Narančić, Zoran Tadić, Dubravko |
author |
Barbero, César Alberto |
author_facet |
Barbero, César Alberto Horvat, Dubravko Krmpotić, Francisco Kuo, T. T. S. Narančić, Zoran Tadić, Dubravko |
author_role |
author |
author2 |
Horvat, Dubravko Krmpotić, Francisco Kuo, T. T. S. Narančić, Zoran Tadić, Dubravko |
author2_role |
author author author author author |
dc.subject.none.fl_str_mv |
Ciencias Exactas Física general shell model formalism nonmesonic weak decay hypernuclei |
topic |
Ciencias Exactas Física general shell model formalism nonmesonic weak decay hypernuclei |
dc.description.none.fl_txt_mv |
A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γ<sub>n</sub> and Γ<sub>p</sub>, which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K*), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of ¹²<sub>Λ</sub>C is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate Γ<sub>NM</sub> = Γ<sub>n</sub> + Γ<sub>p</sub> is of the order of the free Λ decay rate Γ⁰(Γ<sup>th</sup><sub>NM</sub> ≅ Γ⁰) and is consistent with experiments. Yet the measurements of Γ<sub>n/p</sub> = Γ<sub>n</sub> / Γ<sub>p</sub> and of Γ<sub>p</sub> are not well accounted for by the theory (Γ<sup>th</sup><sub>n/p</sub> ≲ 0.42,Γ<sup>th</sup><sub>p</sub> ≳ 0.60Γ⁰). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified. Facultad de Ciencias Exactas |
description |
A general shell model formalism for the nonmesonic weak decay of the hypernuclei has been developed. It involves a partial wave expansion of the emitted nucleon waves, preserves naturally the antisymmetrization between the escaping particles and the residual core, and contains as a particular case the weak Λ-core coupling formalism. The extreme particle-hole model and the quasiparticle Tamm-Dancoff approximation are explicitly worked out. It is shown that the nuclear structure manifests itself basically through the Pauli principle, and a very simple expression is derived for the neutron- and proton-induced decays rates Γ<sub>n</sub> and Γ<sub>p</sub>, which does not involve the spectroscopic factors. We use the standard strangeness-changing weak ΛN→NN transition potential which comprises the exchange of the complete pseudoscalar and vector meson octets (π,η,K,ρ,ω,K*), taking into account some important parity-violating transition operators that are systematically omitted in the literature. The interplay between different mesons in the decay of ¹²<sub>Λ</sub>C is carefully analyzed. With the commonly used parametrization in the one-meson-exchange model (OMEM), the calculated rate Γ<sub>NM</sub> = Γ<sub>n</sub> + Γ<sub>p</sub> is of the order of the free Λ decay rate Γ⁰(Γ<sup>th</sup><sub>NM</sub> ≅ Γ⁰) and is consistent with experiments. Yet the measurements of Γ<sub>n/p</sub> = Γ<sub>n</sub> / Γ<sub>p</sub> and of Γ<sub>p</sub> are not well accounted for by the theory (Γ<sup>th</sup><sub>n/p</sub> ≲ 0.42,Γ<sup>th</sup><sub>p</sub> ≳ 0.60Γ⁰). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified. |
publishDate |
2002 |
dc.date.none.fl_str_mv |
2002-11 |
dc.type.none.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articulo http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
format |
article |
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publishedVersion |
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http://sedici.unlp.edu.ar/handle/10915/125943 |
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dc.language.none.fl_str_mv |
eng |
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eng |
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