https://doi.org/10.1140/epja/i2009-10848-8
Regular Article - Theoretical Physics
meson effects in the Nolen-Schiffer anomaly
1
Departamento de Física, CFM, Universidade Federal de Santa Catarina, CP. 476, CEP 88040-900, Florianópolis, SC, Brazil
2
Instituto de Física, Universidade Federal do Rio Grande do Sul, CEP 91501-970, Porto Alegre, RS, Brazil
3
Departamento de Ciências Exatas e da Natureza, Universidade de Caxias do Sul, CEP 95070-560, Caxias do Sul, RS, Brazil
* e-mail: sidney@fsc.ufsc.br
Received:
7
April
2009
Revised:
18
June
2009
Accepted:
8
July
2009
Published online:
2
August
2009
In this work we revisit the Okamoto-Nolen-Schiffer (ONS) anomaly in the context of four parametrizations of effective hadronic models, two of them with constant couplings between the nucleons and the mesons and two with density-dependent couplings. A Thomas-Fermi approximation is performed and the effects of the isovector-scalar virtual (a
0(980)) mesons are investigated since they influence directly the proton and neutron effective masses in opposite ways. The
-
mixing term is claimed to be important in the explanation of the ONS anomaly and is added in our calculations. We have concluded that as far as the
-
mixing term is included,
M(Z, N) is clearly larger in models with
than in models where this meson is not considered, which is not always the case if the coupling is discarded. None of the models is good enough to describe all experimental data, but the models that better describe the experimental values include the
mesons.
PACS: 21.60.-n Nuclear structure models and methods – / 21.10.Sf Coulomb energies, analogue states – / 24.10.Jv Relativistic models – / 21.30.-x Nuclear forces –
© SIF, Springer-Verlag Berlin Heidelberg, 2009