Non-Mesonic Weak Decay of Lambda-hypernuclei: a new determination of the Gn/Gp ratio

Abstract

Theoretical descriptions of the non-mesonic weak decay of Lambda-hypernuclei are unable to reproduce the experimental values of the ratio Gn/Gp=G(Lambda n -> nn)/G(Lambda p -> np). In this contribution we discuss a new approach to this problem. We have incorporated a one-meson-exchange model for the Lambda N -> nN transition in finite nuclei in an intranuclear cascade code for the calculation of double-coincidence nucleon distributions corresponding to the non-mesonic decay of 5_Lambda-He and 12_Lambda-C. The two-nucleon induced decay mechanism, Lambda np -> nnp, has been taken into account within a local density approximation scheme using a one-pion-exchange model supplemented by short range correlations. A weak decay model independent analysis of preliminary KEK coincidence data for 5_Lambda-He allows us to extract Gn/Gp=0.39 \pm 0.11 when the two-nucleon induced channel is neglected (i.e., G2=0) and Gn/Gp=0.26 \pm 0.11 when G2/G1=0.2.

arXiv comment7 pages, 1 figure. Invited talk at the International Conference on Hypernuclear and Strange Particle Physics (HYP2003), Jefferson Lab, Newport News, Virginia (USA), Oct 14-18, 2003

References in corpus (17)

• Soft-core baryon-baryon potentials for the complete baryon octet
• The Weak Decay of Hypernuclei
• Weak Decay of Lambda Hypernuclei
• Meson exchange in the weak decay of Lambda hypernuclei and the Gamma_n/Gamma_p ratio
• Final State Interactions in Hypernuclear Decay
• Neutron and proton spectra from the decay of $\Lambda$ hypernuclei
• Weak Decay of $\Lambda$ in Nuclei : Quarks vs Mesons
• 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
• Weak Decay of Lambda Hypernuclei
• Nucleon-Nucleon Coincidence Spectra in the Non-Mesonic Weak Decay of Lambda-Hypernuclei and the n/p Puzzle
• Weak decays of medium and heavy 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)]
• $\Lambda N\to NN$ weak interaction in effective field theory
• The Delta I=1/2 rule in non-mesonic weak decay of Lambda-hypernuclei
• Functional approach to the non-mesonic decay of Lambda-hypernuclei

Cited by in corpus (3)

• $\sigma$ meson exchange effect on nonmesonic hypernuclear weak decay observables
• Kinetic energy sum spectra in nonmesonic weak decay of hypernuclei
• Relationships between nonmesonic-weak-decays in different hypernuclei