Microscopic Approach to Nucleon Spectra in Hypernuclear Non-Mesonic Weak Decay

TL;DR

This paper introduces a microscopic diagrammatic method for calculating nucleon spectra in hypernuclear non-mesonic weak decay, incorporating correlations and interactions to improve predictions against experimental data.

Contribution

It is the first to apply a consistent microscopic approach with quantum interference effects to this decay process, extending nuclear matter formalism to finite nuclei.

Findings

Predicted nucleon spectra for 12_Lambda^C show improved agreement with experimental data.

Quantum interference terms significantly influence the spectra predictions.

Discrepancies with proton emission data suggest further refinements are needed.

Abstract

A consistent microscopic diagrammatic approach is applied for the first time to the calculation of the nucleon emission spectra in the non-mesonic weak decay of Lambda-hypernuclei. We adopt a nuclear matter formalism extended to finite nuclei via the local density approximation, a one--meson exchange weak transition potential and a Bonn nucleon-nucleon strong potential. Ground state correlations and final state interactions, at second order in the nucleon--nucleon interaction, are introduced on the same footing for all the isospin channels of one- and two-nucleon induced decays. Single and double--coincidence nucleon spectra are predicted for 12_Lambda^C and compared with recent KEK and FINUDA data. The key role played by quantum interference terms allows us to improve the predictions obtained with intranuclear cascade codes. Discrepancies with data remain for proton emission.