English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

After a short introduction to the nonmesonic weak decay (NMWD) $\Lambda N\gonN$ of $\Lambda$-hypernuclei we discuss the long-standing puzzle on the ratio$\Gamma_n/\Gamma_p$, and some recent experimental evidences that signalizedtowards its final solution. Two versions of theIndependent-Particle-Shell-Model (IPSM) are employed to account for the nuclearstructure of the final residual nuclei. They are: (a) IPSM-a, where nocorrelation, except for the Pauli principle, is taken into account, and (b)IPSM-b, where the highly excited hole states are considered to bequasi-stationary and are described by Breit-Wigner distributions, whose widthsare estimated from the experimental data. We evaluate the coincidence spectrain $^{4}_\Lambda$He, $^{5}_\Lambda$He, $^{12}_\Lambda$C, $^{16}_\Lambda$O, and$^{28}_\Lambda$Si, as a function of the sum of kinetic energies$E_{nN}=E_n+E_N$ for $N=n,p$. The recent Brookhaven National Laboratoryexperiment E788 on $^4_\Lambda$He, is interpreted within the IPSM . We foundthat the shapes of all the spectra are basically tailored by the kinematics ofthe corresponding phase space, depending very weakly on the dynamics, which isgauged here by the one-meson-exchange-potential. In spite of thestraightforwardness of the approach a good agreement with data is achieved.This might be an indication that the final-state-interactions and thetwo-nucleon induced processes are not very important in the decay of thishypernucleus. We have also found that the $\pi+K$ exchange potential with softvertex-form-factor cutoffs $(\Lambda_\pi\approx 0.7$ GeV, $\Lambda_K\approx0.9$ GeV), is able to account simultaneously for the available experimentaldata related to $\Gamma_p$ and $\Gamma_n$ for $^4_\Lambda$H, $^4_\Lambda$He,and $^5_\Lambda$He.

Nonmesonic weak decay of Lambda-hypernuclei within independent-particle shell-model