Quantum interference terms in nonmesonic weak decay of $\Lambda$-hypernuclei

E. BAUER

NUCLEAR PHYSICS A

Elsevier

Lugar: Amsterdam; Año: 2007 vol. 796 p. 11 - 40

0375-9474

Single and double coincidence nucleon spectra in the $\Lambda$-hypernuclei weak decay are evaluated and discussed using a microscopic formalism. Nuclear matter is employed together with the local density approximation which allows us to analyze the $^{12}_{\Lambda}C$ hypernucleus non-mesonic weak decay. Final state interactions ($FSI$) are included via the first order (in the nuclear residual interaction) terms to the RPA, where the strong residual interaction is modelled by a Bonn potential. At this level of approximation, these $FSI$ are pure quantum interference terms between the primary decay $(\Lambda N \rightarrow NN)$ and $(\Lambda N \rightarrow NN \rightarrow NN)$, where the strong interaction is responsible for the last piece in the second reaction. Also the Pauli exchange contributions are explicitly evaluated. We show that the inclusion of Pauli exchange terms is important. A comparison with data is made. We conclude that the limitations in phase space in the RPA makes this approximation inadequate to reproduce the  nucleon spectra. This fact, does not allow us to draw a definite conclusion about the importance of the interference terms.