literature
Literature
Authors
Jobs
Seminars
Conferences
DataBETA
reference search24 citations

Citations per year

20022005200820112014012345
Abstract: (APS)
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 Λ12C 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(ΓNMth≅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 (Γn/pth≲0.42,Γpth≳0.60Γ0). It is suggested that, unless additional degrees of freedom are incorporated, the OMEM parameters should be radically modified.
  • 21.80.+a
  • 21.60.-n
  • 25.80.Pw
  • 13.75.Ev
Loading ...