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We derive general explicit expressions for a shell-model calculation of the intrinsic asymmetry parameter, $a_\Lambda$, in nonmesonic weak hypernuclear decay. They include the effects of three-body kinematics in the final states of the…

Nuclear Theory · Physics 2016-09-08 Cesar Barbero , Alfredo P. Galeao , Francisco Krmpotic

The nonmesonic weak decay of $\Lambda$ hypernuclei using nonrelativistic nuclear matter is studied. As the basic building block we use the Polarization Propagator Method developed by Oset and Salcedo. It is shown that the exact calculation…

Nuclear Theory · Physics 2016-09-08 E. Bauer , F. Krmpotic

I review the current status of understanding the mechanism of the nonmesonic weak decays (NMWD) of hypernuclei. Long standing problem on the Gamma_n/Gamma_p ratio has been solved by considering short-range weak interactions properly. This…

Nuclear Theory · Physics 2009-11-10 Makoto Oka

We develop a theoretical framework for the evaluation of the coincidence number of pairs, $N_{nN}$, and the asymmetry parameter, $a_\Lambda$, in nonmesonic hypernuclear decay $\Lambda N\rightarrow nN$. The primary nomesonic weak…

Nuclear Theory · Physics 2010-05-06 C. Barbero , A. Mariano , S. B. Duarte

The weak nonmesonic decay of Lambda-hypernuclei is studied in the context of a one-meson-exchange model. Predictions are made for the decay rate, p/n stimulation ratio and the asymmetry in polarized hypernuclear decay.

Nuclear Theory · Physics 2008-11-26 John F. Dubach , Geoffrey B. Feldman , Barry R. Holstein , Lorenzo de la Torre

The results of a measurement of the proton spectra following the Non--Mesonic Weak Decay of $\mathrm{^5_{\Lambda}He}$, $\mathrm{^7_{\Lambda}Li}$ and $\mathrm{^{12}_{\Lambda}C}$ are presented and discussed. The experiment was performed at…

Nuclear Experiment · Physics 2019-08-13 M. Agnello

A fully relativistic finite nucleus wave-function approach to the non-mesonic weak decay of the ${_\Lambda^{12} C}$ hypernucleus is presented. The model is based on the calculation of the amplitudes of the tree-level Feynman diagrams for…

Nuclear Theory · Physics 2015-03-13 Francesco Conti , Andrea Meucci , Carlotta Giusti. Franco Davide Pacati

We have obtained the decay asymmetry parameters in non-mesonic weak decay of polarized Lambda-hypernuclei by measuring the proton asymmetry. The polarized Lambda-hypernuclei, 5_Lambda-He, 12_Lambda-C, and 11_Lambda-B, were produced in high…

We have measured the energy spectra of pions and protons emitted in the weak decay of 12_Lambda_C, 28_Lambda_Si, and Lambda_Fe hypernuclei produced via the (pi+, K+) reaction. The decay widths of the pi- mesonic decay (Lambda -> p + pi-)…

We present a study of the nonmesonic weak decay (NMWD) of charmed hypernuclei using a relativistic formalism. We work within the framework of the independent particle shell model and employ a ($\pi$,$K$) one-meson-exchange model for the…

Nuclear Theory · Physics 2018-01-17 C. E. Fontoura , F. Krmpotić , A. P. Galeão , C De Conti , G. Krein

The focus of these Lectures is on the weak decay modes of hypernuclei, with special attention to Lambda-hypernuclei. The subject involves many fields of modern theoretical and experimental physics, from nuclear structure to the fundamental…

Nuclear Theory · Physics 2007-05-23 W. M. Alberico , G. Garbarino

We analyze the influence of $\sigma$ meson exchange on the main nonmesonic hypernuclear weak decay observables: the total rate, $\Gamma_{NM}$, the neutron-to-proton branching ratio, $\Gamma_{n/p}$, and the proton asymmetry parameter,…

Nuclear Theory · Physics 2008-11-26 C. Barbero , A. Mariano

We derive in detail the transition potential for nonmesonic lambda-hypernuclear decay in a one-meson-exchange model involving the full pseudoscalar and vector meson octets and including two effects that have been systematically omitted in…

Nuclear Theory · Physics 2009-11-07 C. Barbero , C. De Conti , A. P. Galeao , F. Krmpotic

The non-mesonic weak decay of polarized Lambda-hypernuclei is studied for the first time by taking into account, with a Monte Carlo intranuclear cascade code, the nucleon final state interactions. A one-meson-exchange model is employed to…

Nuclear Theory · Physics 2016-09-08 W. M. Alberico , G. Garbarino , A. Parreno , A. Ramos

Nonmesonic weak decays of s-shell hypernuclei are analyzed in microscopic models for the Lambda N to NN weak interaction. A scalar-isoscalar meson, sigma, is introduced and its importance in accounting the decay rates, n/p ratios and proton…

Nuclear Theory · Physics 2009-11-10 K. Sasaki , M. Izaki , M. Oka

Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the ratio of the two-nucleon and the one-proton induced decay widths, Gamma_2N/Gamma_p, are…

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…

Nuclear Theory · Physics 2009-11-10 G. Garbarino , A. Parreno , A. Ramos

The ratio N_{nn}/N_{np} between the number of neutron-neutron and neutron--proton pairs emitted in the non--mesonic weak decay of \Lambda-hypernuclei is calculated within a nuclear matter formalism extended to ^{12}_{Lambda}C via the local…

Nuclear Theory · Physics 2015-05-18 E. Bauer , G. Garbarino

We present a nonrelativistic transition potential for the weak strangeness-changing reaction $\Lambda N \to NN$. The potential is based on a one meson exchange model (OME), where, in addition to the long-ranged pion, the exchange of the…

Nuclear Theory · Physics 2009-10-31 A. Parreño , C. Bennhold , A. Ramos

In this review we discuss the present status of strange nuclear physics, with special attention to the weak decay of Lambda hypernuclei. The models proposed for the evaluation of the Lambda decay widths are summarized and their results are…

Nuclear Theory · Physics 2009-11-07 W. M. Alberico , G. Garbarino