Search results for "LOCI"
showing 10 items of 1277 documents
ββ2νdecay in48Ca
2001
A schematic study of the $\ensuremath{\beta}\ensuremath{\beta}2\ensuremath{\nu}$ decay of ${}^{48}\mathrm{Ca}$ is made in a shell-model approach. The emphasis is especially put on the role of the spin-orbit potential in relation with the contribution of other terms in the strong interaction. This is discussed with a particular attention to the behavior of these ones under the SU(4) symmetry. Different methods in calculating the transition amplitude are also looked at with the aim to determine their reliability and, eventually, why they do not work. Further aspects relative to the failure of the operator expansion method to reproduce the results of more elaborate calculations are examined.
First observation of beta-delayed deuteron emission
1990
5 pages, 2 figures.
β-delayed fission of186,188Bi isotopes
2013
By using the technique of correlating implanted evaporation residues and their subsequent fission decay, $\ensuremath{\beta}$-delayed fission ($\ensuremath{\beta}$DF) of ${}^{186}$Bi has been identified for the first time and $\ensuremath{\beta}$DF of ${}^{188}$Bi has been unambiguously confirmed. The experiments were performed at the velocity filter SHIP (GSI, Darmstadt). The $\ensuremath{\beta}$DF probabilities for both nuclides were qualitatively estimated, and, in particular indications for a large value in the case of ${}^{186}$Bi are regarded.
Neutrinoless double beta decay to excited collective 0+ states
2000
Abstract The many recently performed experiments to study the two-neutrino double beta (2 νββ ) decay to the first excited 0 + final state encourage similar experiments to be done for the neutrinoless double beta (0 νββ ) decay. Based on the accumulated theoretical and experimental information on the 2 νββ decays one could hope that the 0 νββ decay to the excited 0 + state would be very efficient in restricting the parameter space of modern particle-physics theories. In this article the 0 νββ decays of 76 Ge and 82 Se to excited collective 0 + states are studied within a realistic nuclear model. It is found that the lower limits for the half-lives of these decays are of the order of 10 27 y…
Theory of double beta decay
2005
Basic features of the two-neutrino double beta ( 2 ν β β ) decay and neutrinoless double beta ( 0 ν β β ) decay are discussed. A short review of the most important nuclear models, used to describe the ββ decay, is given. A deeper survey of the nuclear matrix elements, related to the above-mentioned decay modes, is performed using the proton-neutron quasiparticle random-phase approximation (pnQRPA). In particular, the extraction of a proper value of the proton-neutron particle-particle interaction parameter in this theory is addressed. The relevance of different multipoles in the multipole decomposition of the 0 ν β β matrix element is also discussed in the pnQRPA framework.
Proton-Neutron QRPA
2007
We discussed proton—neutron two-quasiparticle excitations and their electromagnetic and beta decays in Chap. 15. In Chap. 17 we introduced the pn-QTDA, the simplest configuration mixing scheme of these excitations. The vacuum of the pnQTDA is the BCS vacuum, and the solutions of the pn-QTDA satisfy a variational principle.1
Probing the quenching of gA by single and double beta decays
2013
Abstract Ground-state-to-ground-state two-neutrino double beta ( 2 ν β β ) decays and single beta (EC and β − ) decays are studied for the A = 100 (100Mo 100Tc 100Ru), A = 116 (116Cd 116In 116Sn) and A = 128 (128Te 128I 128Xe) nuclear systems by using the proton–neutron quasiparticle random-phase approximation exploiting realistic effective interactions in very large single-particle bases. The aim of this exercise is to see if both the single-beta and double-beta decay observables related to the ground states of the initial, intermediate and final nuclei participant in the decays can be described simultaneously by changing the value of the axial-vector coupling constant g A . In spite of th…
Neutrino-nuclear responses for astro-neutrinos, single beta decays and double beta decays
2019
Abstract Neutrino–nuclear responses associated with astro-neutrinos, single beta decays and double beta decays are crucial in studies of neutrino properties of interest for astro-particle physics. The present report reviews briefly recent studies of the neutrino–nuclear responses from both experimental and theoretical points of view in order to obtain a consistent understanding of the many facets of the neutrino–nuclear responses. Subjects discussed in this review include (i) experimental studies of neutrino–nuclear responses by means of single beta decays, charge-exchange nuclear reactions, muon- photon- and neutrino–nuclear reactions, and nucleon-transfer reactions, (ii) implications of a…
A velocity–diffusion method for a Lotka–Volterra system with nonlinear cross and self-diffusion
2009
The aim of this paper is to introduce a deterministic particle method for the solution of two strongly coupled reaction-diffusion equations. In these equations the diffusion is nonlinear because we consider the cross and self-diffusion effects. The reaction terms on which we focus are of the Lotka-Volterra type. Our treatment of the diffusion terms is a generalization of the idea, introduced in [P. Degond, F.-J. Mustieles, A deterministic approximation of diffusion equations using particles, SIAM J. Sci. Stat. Comput. 11 (1990) 293-310] for the linear diffusion, of interpreting Fick's law in a deterministic way as a prescription on the particle velocity. Time discretization is based on the …
Direct Analysis of Psilocin and Muscimol in Urine Samples Using Single Drop Microextraction Technique In-Line with Capillary Electrophoresis
2020
The fully automated system of single drop microextraction coupled with capillary electrophoresis (SDME-CE) was developed for in-line preconcentration and determination of muscimol (MUS) and psilocin (PSC) from urine samples. Those two analytes are characteristic active metabolites of Amanita and Psilocybe mushrooms, evoking visual and auditory hallucinations. Study analytes were selectively extracted from the donor phase (urine samples, pH 4) into the organic phase (a drop of octanol layer), and re-extracted to the acidic acceptor (background electrolyte, BGE), consisting of 25 mM phosphate buffer (pH 3). The optimized conditions for the extraction procedure of a 200 µ