Parreño, AssumptaRamos, ÀngelsHernández Martín, Óscar2022-04-262022-04-262020Hernández Martín, Ó. (2020). On the validity of the ∆I = 1 / 2 Isospin Rule and the Block–Dalitz Model in Hypernuclear Non–mesonic Weak Decay. (Trabajo Fin de Máster Inédito). Universidad de Sevilla, Sevilla.https://hdl.handle.net/11441/132660Abstract A study of the non–mesonic weak decay of light hypernuclei is performed on the basis of the Block–Dalitz approach which allows one to extract the elemen- tary Λ N → nN decay amplitudes and rates without detailed knowledge of the microscopic interaction mechanism. The present work analyses the validity of this approach using decay rates calculated within a one–meson–exchange tran- sition potential supplemented by a two–pion–exchange mechanism. It is found that although the Block–Dalitz model is a reliable approximation for predicting the decay rates of s –shell hypernuclei, it fails to reproduce the 5 Λ He asymmetry parameter. Possible ∆ I = 3 / 2 isospin contributions to the non–mesonic decay rates are also investigated within the factorization approximation. Unfortu- nately, the experimental data are still of limited precision and therefore, it is not possible to extract the degree of violation of the ∆ I = 1 / 2 isospin rule. The present study introduces improvements on preceding theoretical models and, together with forthcoming J–PARC data on the non–mesonic decay of four– body hypernuclei, it will play an important role in establishing the detailed spin–isospin dependence of the Λ N → nN process as well as in the design of theoretical models.80 p.engAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccess