skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: {sigma} meson exchange effect on non-mesonic hypernuclear weak decay observables

Abstract

We analyze the influence of {sigma} meson exchange on the main non-mesonic hypernuclear weak decay observables: Total rate {gamma}{sub NM}, neutron-to-proton branching ratio {gamma}{sub n/p}, and proton asymmetry parameter a{sub {lambda}}. The {sigma} meson exchange is added to the standard strangeness-changing weak {lambda}N{yields}NN transition potential, which includes the exchange of the complete pseudoscalar and vector mesons octet ({pi},{eta},K,{rho},{omega},K{sup *}). Using a shell model formalism, the {sigma} meson weak coupling constants are adjusted to reproduce the recent {gamma}{sub NM} and {gamma}{sub n/p} experimental data for {sub {lambda}}{sup 5}He. Numerical results for the remaining observables of {sub {lambda}}{sup 5}He and all the observables of {sub {lambda}}{sup 12}C decays are presented. They clearly show that the addition of the {sigma} meson improves the agreement with the data. However, its effect it is not enough to reproduce well the a{sub {lambda}} values, which means that other improvements of the model must be explored to explain the puzzle posed by the experiments.

Authors:
;  [1]
  1. Departamento de Fisica, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina)
Publication Date:
OSTI Identifier:
20771260
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.73.024309; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ASYMMETRY; BOSON-EXCHANGE MODELS; BRANCHING RATIO; CARBON 12; COUPLING CONSTANTS; HELIUM 5; HYPERNUCLEI; LAMBDA BARYONS; NEUTRONS; NUCLEAR DECAY; NUCLEON-HYPERON INTERACTIONS; POTENTIALS; PROTONS; PSEUDOSCALAR MESONS; SHELL MODELS; STRANGENESS; VECTOR MESONS; WEAK INTERACTIONS

Citation Formats

Barbero, C., and Mariano, A. {sigma} meson exchange effect on non-mesonic hypernuclear weak decay observables. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.024309.
Barbero, C., & Mariano, A. {sigma} meson exchange effect on non-mesonic hypernuclear weak decay observables. United States. doi:10.1103/PhysRevC.73.024309.
Barbero, C., and Mariano, A. Wed . "{sigma} meson exchange effect on non-mesonic hypernuclear weak decay observables". United States. doi:10.1103/PhysRevC.73.024309.
@article{osti_20771260,
title = {{sigma} meson exchange effect on non-mesonic hypernuclear weak decay observables},
author = {Barbero, C. and Mariano, A.},
abstractNote = {We analyze the influence of {sigma} meson exchange on the main non-mesonic hypernuclear weak decay observables: Total rate {gamma}{sub NM}, neutron-to-proton branching ratio {gamma}{sub n/p}, and proton asymmetry parameter a{sub {lambda}}. The {sigma} meson exchange is added to the standard strangeness-changing weak {lambda}N{yields}NN transition potential, which includes the exchange of the complete pseudoscalar and vector mesons octet ({pi},{eta},K,{rho},{omega},K{sup *}). Using a shell model formalism, the {sigma} meson weak coupling constants are adjusted to reproduce the recent {gamma}{sub NM} and {gamma}{sub n/p} experimental data for {sub {lambda}}{sup 5}He. Numerical results for the remaining observables of {sub {lambda}}{sup 5}He and all the observables of {sub {lambda}}{sup 12}C decays are presented. They clearly show that the addition of the {sigma} meson improves the agreement with the data. However, its effect it is not enough to reproduce well the a{sub {lambda}} values, which means that other improvements of the model must be explored to explain the puzzle posed by the experiments.},
doi = {10.1103/PhysRevC.73.024309},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 73,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}