Dynamics of Hypernuclear Nonmesonic Weak Decay

Violation of the ∆I=1/2 rule in the nonmesonic weak decay of hypernuclei

Violations of the ∆I=1/2 rule are investigated in the nonmesonic weak hypernuclear decay using a weak ΛN→NN transition potential based on meson exchange. While the weak ∆I=3/2 couplings of baryons to pseudoscalar mesons are known to be very small, the analogous couplings of baryons to vector mesons are not known experimentally. These couplings have been evaluated using the factorization approxi...

Intrinsic asymmetry parameter in nonmesonic hypernuclear decay: analytical proof of the independence on hypernucleus within an independent particle shell model

We derive general analytical expressions for the evaluation of the intrinsic asymmetry parameter in nonmesonic hypernuclear weak decay, within an independent particle shell model framework. Present formalism is valid for even-even, even-odd and odd-odd core hypernucleus. A standard strangeness-changing weak transition potential with exchange of the complete meson octet (π,η,K,ρ,ω,K∗) is assumed...

Role of the axial vector a1-meson exchange in hypernuclear nonmesonic weak decays

0 Chiral symmetry and meson exchange approach to hypernuclear decay

We take an approach to the Λ nonmesonic weak decay in nuclei based on the exchange of mesons under the guidelines of chiral Lagrangians. The one pion and one kaon exchange are considered, together with the exchange of two pions, either correlated, leading to an important scalar-isoscalar exchange (σ-like exchange), or uncorrelated (box diagrams). A drastic reduction of the OPE results for the Γ...

ar X iv : n uc l - th / 9 71 10 49 v 2 5 J an 1 99 9 π + Emission from Hypernuclei and the Weak ∆ I = 3 / 2 Transitions

Low energy π emission in hypernuclear weak decays is studied in the soft pion limit. It is found that the π decay amplitude is dominated by the ∆I = 3/2 part of nonmesonic weak decays according to the soft pion theorem. The ratios, R(π/soft π−), for light hypernuclei are estimated in the direct quark mechanism, which predicts violation of the ∆I = 1/2 rule, and found to be about 1/3 for 4ΛHe. ∗...