Nucleon-Nucleon Coincidence Spectra in the Non-Mesonic Weak Decay of Lambda-Hypernuclei and the n/p Puzzle
Abstract
The main open problem in the physics of Lambda-hypernuclei is the lack of a sound theoretical interpretation of the large experimental values for the ratio Gn/Gp. To approach the problem, we have incorporated a Lambda N-> nN one-meson-exchange model in an intranuclear cascade code for a finite nucleus calculation of the nucleon-nucleon (angular and energy) coincidence distributions in the non-mesonic weak decay of 5Lambda-He and 12Lambda-C hypernuclei. The two-nucleon induced decay mechanism, Lambda np-> nnp, has been taken into account by means of the polarization propagator formalism in local density approximation. With respect to single nucleon spectra studies, the treatment of two-nucleon correlations allow a cleaner and more direct determination, from data, of Gn/Gp. Our results agree with the preliminary coincidence data of KEK-E462 for 5Lambda-He. This allows us to conclude that Gn/Gp for 5Lambda-He should be close to 0.46, the value predicted by our one-meson-exchange model for this hypernucleus. Unfortunately, to disentangle one- and two-body induced decay channels from experimental non-mesonic decay events, three-nucleon coincidences should be measured.
Turn this paper into a full lesson
ArcXiv compiles a staged curriculum from this paper: 8-12 lessons across beginner → advanced, synthesised section guides, visuals, flashcards, a quiz, exercises, and on-demand deep dives per section. Grounded in the abstract, never invented.