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

G. Garbarino·A. Parreno·A. Ramos
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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.

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G. Garbarino, A. Parreno, A. Ramos. 2003-12-12. Non-Mesonic Weak Decay of Lambda-hypernuclei: a new determination of the Gn/Gp ratio. https://doi.org/10.1016/j.nuclphysa.2004.12.071

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