On the role of ground state correlations in hypernuclear non-mesonic weak decay

Abstract

The contribution of ground state correlations (GSC) to the non--mesonic weak decay of ${}_{\Lambda }^{12}$C and other medium to heavy hypernuclei is studied within a nuclear matter formalism implemented in a local density approximation. We adopt a weak transition potential including the exchange of the complete octets of pseudoscalar and vector mesons as well as a residual strong interaction modeled on the Bonn potential. Leading GSC contributions, at first order in the residual strong interaction, are introduced on the same footing for all isospin channels of one-- and two--nucleon induced decays. Together with fermion antisymmetrization, GSC turn out to be important for an accurate determination of the decay widths. Besides opening the two--nucleon stimulated decay channels, for ${}_{\Lambda }^{12}$C GSC are responsible for 14% of the rate ${\Gamma }_1$ while increasing the ${\Gamma }_n/{\Gamma }_p$ ratio by 4%. Our final results for ${}_{\Lambda }^{12}$C are: ${\Gamma }_{\mathrm{NM}}=0.98$, ${\Gamma }_n/{\Gamma }_p=0.34$ and ${\Gamma }_2/{\Gamma }_{\mathrm{NM}}=0.26$. The saturation property of ${\Gamma }_{\mathrm{NM}}$ with increasing hypernuclear mass number is clearly observed. The agreement with data of our predictions for ${\Gamma }_{\mathrm{NM}}$, ${\Gamma }_n/{\Gamma }_p$ and ${\Gamma }_2$ is rather good.

32 pages, 9 figures

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• Microscopic Approach to Nucleon Spectra in Hypernuclear Non-Mesonic Weak Decay
• Microscopic approach to the proton asymmetry in the non-mesonic weak decay of Lambda-hypernuclei
• Relationships between nonmesonic-weak-decays in different hypernuclei
• On the effect of the Delta(1232) in hypernuclear non-mesonic weak decay: a microscopic approach
• Nonmesonic weak decay spectra of light hypernuclei
• Nonmesonic Weak Decay Dynamics from proton spectra of $\Lambda$-Hypernuclei
• Nonmesonic Weak Decay of $\Lambda$ Hypernuclei: The Three--Nucleon Induced Mode