Single and double coincidence nucleon spectra in the weak decay of Lambda hypernuclei

Abstract

Recent progress has been experienced in the field of hypernuclear weak decay, especially concerning the ratio of the neutron- to proton-induced Lambda non-mesonic decay rates, G_n/G_p. Theoretical analyses of nucleon coincidence data have been performed in a finite nucleus framework. They led to the extraction of G_n/G_p values in agreement with pure theoretical estimates, thus providing an evidence for the solution of a longstanding puzzle. Here we present an alternative approach to the problem, based on a nuclear matter formalism extended to finite nuclei via the local density approximation. The work is motivated by the exigence to make the determination of G_n/G_p from data less model dependent. One-meson-exchange potentials are used for describing both the one- and two-nucleon induced decays, Lambda N -> n N and Lambda N N -> n N N. For the latter, treated within a microscopic approach, the channels Lambda n n -> n n n and Lambda p p -> n p p are included in addition to the mode Lambda n p -> n n p already considered, in a phenomenological way, in previous studies. The propagation of the final nucleons in the residual nucleus is simulated by an intranuclear cascade code. We evaluate single and double coincidence nucleon spectra for the non-mesonic decay of C-12-Lambda. Through the comparison of our predictions with KEK coincidence data we determine G_n/G_p=0.43 \pm 0.10 for this hypernucleus, confirming previous finite nucleus analyses.

34 pages, 17 figures

References in corpus (24)

• Weak Decay of Lambda Hypernuclei
• First Results on 12Lambda-C production at DAPHNE
• Towards the solution of the Gn/Gp Puzzle in the Non-Mesonic Weak Decay of Lambda-Hypernuclei
• Neutron and proton energy spectra from the non-mesonic weak decays of 5_Lambda-He and 12_Lambda-C
• Coincidence Measurement of the Nonmesonic Weak Decay of ^{12}_{Lambda}C
• Exclusive Measurement of the Nonmesonic Weak Decay of ^{5}_ΛHe Hypernucleus
• Mesonic and nonmesonic weak decay widths of medium-heavy lambda hypernuclei
• Nucleon-Nucleon Coincidence Spectra in the Non-Mesonic Weak Decay of Lambda-Hypernuclei and the n/p Puzzle
• New results on Mesonic Weak Decay of $p$-shell $\Lambda$-Hypernuclei
• Nonmesonic weak decay of light hypernuclei with coherent $\Sigma$ mixing
• Erratum: Neutron and proton spectra from the decay of $\Lambda$ hypernuclei [Phys. Rev. C55, 735 (1997)]
• Sigma Exchange in the Nonmesonic Decays of Light Hypernuclei and Violation of the Delta I=1/2 Rule
• Measurement of the proton spectra from Non-Mesonic Weak Decay of ${}_{\Lambda }^{5}He$, ${}_{\Lambda }^{7}Li$ and ${}_{\Lambda }^{12}C$
• $\Lambda N\to NN$ weak interaction in effective field theory
• Exchange terms in the two--nucleon induced non--mesonic weak decay of $\Lambda$--hypernuclei
• Two-pion-exchange in the non-mesonic weak decay of $\Lambda$-hypernuclei
• Asymmetries in the Non-Mesonic Weak Decay of Polarized Lambda-Hypernuclei
• Kinematical and nonlocality effects on the nonmesonic weak hypernuclear decay
• Weak decays of 4He-Lambda
• Asymmetry parameter for nonmesonic hypernuclear decay
• Nonmesonic Weak Decay of $\Lambda$ Hypernuclei within a Nuclear Matter Formalism
• $\sigma$ meson exchange effect on nonmesonic hypernuclear weak decay observables
• An EFT for the weak $\Lambda N$ interaction
• Ground state normalization in the nonmesonic weak decay of ${}_{\Lambda }^{12}C$ hypernucleus within a nuclear matter formalism

Cited by in corpus (13)

• Strangeness in nuclear physics
• Strangeness nuclear physics: a critical review on selected topics
• Proton spectra from Non-Mesonic Weak Decay of p-shell Lambda-Hypernuclei and evidence for the two-nucleon induced process
• Measurement of the proton spectra from Non-Mesonic Weak Decay of ${}_{\Lambda }^{5}He$, ${}_{\Lambda }^{7}Li$ and ${}_{\Lambda }^{12}C$
• On the role of ground state correlations in hypernuclear non-mesonic weak decay
• First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell Λ-Hypernuclei
• 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