Nonmesonic weak decay spectra of ${}_{\Lambda }^4$He

Abstract

To comprehend the recent Brookhaven National Laboratory experiment E788 on ${}_{\Lambda }^4$He, we have outlined a simple theoretical framework, based on the independent-particle shell model, for the one-nucleon-induced nonmesonic weak decay spectra. Basically, the shapes of all the spectra are tailored by the kinematics of the corresponding phase space, depending very weakly on the dynamics, which is gauged here by the one-meson-exchange-potential. In spite of the straightforwardness of the approach a good agreement with data is acheived. This might be an indication that the final-state-interactions and the two-nucleon induced processes are not very important in the decay of this hypernucleus. We have also found that the $\pi +K$ exchange potential with soft vertex-form-factor cutoffs $({\Lambda }_{\pi }\approx 0.7$ GeV, ${\Lambda }_K\approx 0.9$ GeV), is able to account simultaneously for the available experimental data related to ${\Gamma }_p$ and ${\Gamma }_n$ for ${}_{\Lambda }^4$H, ${}_{\Lambda }^4$He, and ${}_{\Lambda }^5$He.

12 pages, 4 figures, 1 table, submitted for publication; v2: major revision, 18 pages, one author added, table, figures and bibliography changed

References in corpus (20)

• Hypernuclear Physics for Neutron Stars
• The Weak Decay of Hypernuclei
• The ${}^8$B Neutrino Spectrum
• Theory of Weak Hypernuclear Decay
• Final State Interactions in Hypernuclear Decay
• 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
• Non-mesonic Weak Decays of Light Hypernuclei in the Direct Quark and the One-Pion Exchange Mechanisms
• Nonmesonic weak decay of light hypernuclei with coherent $\Sigma$ mixing
• 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 ${}_{\Lambda }^{12}C$
• Two-pion-exchange in the non-mesonic weak decay of $\Lambda$-hypernuclei
• Kinematical and nonlocality effects on the nonmesonic weak hypernuclear decay
• Asymmetries in the Non-Mesonic Weak Decay of Polarized Lambda-Hypernuclei
• Weak decays of 4He-Lambda
• Asymmetry parameter for nonmesonic hypernuclear decay
• Kinetic energy sum spectra in nonmesonic weak decay of hypernuclei
• s-Wave Approximation for Asymmetry in Nonmesonic Decay of Finite Hypernuclei
• Nucleon-nucleon coincidence measurement in the non-mesonic weak decay of 5_Lambda-He and 12_Lambda-C hypernuclei

Cited by in corpus (7)

• Relationships between nonmesonic-weak-decays in different hypernuclei
• Weak nonmesonic decay spectra of hypernuclei
• Nonmesonic Hyperon Weak Decay Spectra in ${}_{\Lambda }^{12}$C}
• Nonmesonic weak decay spectra of light hypernuclei
• Nonmesonic Weak Decay Dynamics from proton spectra of $\Lambda$-Hypernuclei
• Final state interaction in the pn and nn decay channels of ${}_{\Lambda }^4$He
• Delayed clusters accompanying nonmesonic weak decay of the $\Lambda$-hypernuclei: a clue to nonleptonic processes