Search results for "nucleus"
showing 10 items of 1803 documents
Clustering effects in 48Cr composite nucleus produced via the reaction 24Mg + 24Mg at the excitation energy of 60 MeV
2013
The reaction 24Mg + 24Mg was used to produce the composite nucleus 48Cr at 60 MeV of excitation energy where a narrow resonance (170 KeV) has been found by measuring the elastic and inelastic channels. To determine the occurrence of deformation of this compound nucleus and its possible connection with the resonances and the hypothetical cluster structure, evaporative Light Charged Particles (LCP) were measured and compared to Statistical Model (SM) predictions. The experiment was performed at LNL using the 8πLP apparatus. The comparison of the evaporation residue-LCP coincidence angular distributions and LCP energy spectra with SM calculations supports the presence of a very large deformati…
First prompt in-beam γ-ray spectroscopy of a superheavy element: the256Rf
2013
Using state-of-the-art γ-ray spectroscopic techniques, the first rotational band of a superheavy element, extending up to a spin of 20 , was discovered in the nucleus 256Rf. To perform such an experiment at the limits of the present instrumentation, several developments were needed. The most important of these developments was of an intense isotopically enriched 50Ti beam using the MIVOC method. The experimental set-up and subsequent analysis allowed the 256Rf ground-state band to be revealed. The rotational properties of the band are discussed and compared with neighboring transfermium nuclei through the study of their moments of inertia. These data suggest that there is no evidence of a s…
Physics of nuclear processes triggered by the interplay of strong and weak interactions
2012
Neutrinoless double beta (0νββ) decay of nuclei is a process that requires the neutrino to be a massive Majorana particle and thus cannot proceed in the standard model of electro-weak interactions. Recent results of the neutrino-oscillation experiments have produced accurate information on the mixing of neutrinos and their squared mass differences. The 0νββ decay takes place in atomic nuclei where it can be observed, at least in principle, by underground neutrino experiments. The information about the weak-interaction observables, like the neutrino mass, has to be filtered from the data through the nuclear matrix elements (NMEs). In this article recent work of the Jyv¨askyl¨a group on the N…
Studies of astrophysically interesting nucleus23Al
2010
We have studied the β-delayed proton decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton branching of the IAS in 23Mg and to determine the absolute proton branchings by combining our results to the latest βγ-decay data. We have made also a high precision mass measurement of the ground state of 23Al to establish more accurate proton separation energy of 23Al. Here the description of the used techniques along with preliminary results of the experiments are given.
Single Particle Levels and ββ-Decay Matrix Elements in The Interacting Boson Model
2018
Recently a new method to calculate the occupancies of single particle levels in atomic nuclei was developed in the context of the microscopic interacting boson model, in which neutron and proton degrees of freedom are treated explicitly (IBM-2). The energies of the single particle levels constitute a very important input for the calculation of the occupancies in this method, and further they play important role in the calculation of double beta decay nuclear matrix elements. Here we discuss how the 0νββ, 0νhββ, and 2νββ-decay nuclear matrix elements (NMEs) are affected when the energies of single particle levels are changed. peerReviewed
Exotic shapes and clusterization of atomic nuclei
2010
Shape isomers, including superdeformed and hyperderformed states can be determined from the quasi-dynamical SU(3) symmetry based on the Nilsson-model. We investigate the possible binary clusterizations of these shape isomers. The allowed cluster-configurations give a hint for the favourable reaction channels for populating these states. Our semimicroscopic approach is largely based on symmetry considerations, combined with energetic preference calculations. As illustrative examples some results for the 36Ar, 40Ca and 56Ni nuclei are shown.
How can the nucleus be lighter than its constituents?
2021
Abstract The fact that the nucleus is lighter than its constituents, seems rather strange. How can the whole have a smaller mass than its components? To get some intuition about how this is possible, one can look at a simpler more familiar system exhibiting the same phenomena; the hydrogen atom. It turns out that the same is true here; the hydrogen atom is a little bit lighter than the sum of its constituents. This difference corresponds to the ionisation energy of hydrogen. This observation allows a simple explanation for how this is possible; the destructive interference between the electric fields of the proton and electron causes a reduction in the energy of the electric field and hence…
Decay of theN=126, Fr213nucleus
2016
gamma rays following the EC/beta(+) and alpha decay of the N = 126, Fr-213 nucleus have been observed at the CERN isotope separator on-line (ISOLDE) facility with the help of gamma-ray and conversion-electron spectroscopy. These gamma rays establish several hitherto unknown excited states in Rn-213. Also, five new a-decay branches from the Fr-213 ground state have been discovered. Shell model calculations have been performed to understand the newly observed states in Rn-213.
Coulomb excitation of pear-shaped nuclei
2019
There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we have observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable condition…
Spontaneous fission instability of the neutron-deficient No and Rf isotopes: The new isotope No249
2021
In the heaviest elements, the instability of atomic nuclei against spontaneous fission leads to ever shorter nuclear half-lives. Upon falling below a timescale of ${10}^{\ensuremath{-}14}$ s, the border of existence of isotopes is crossed because this is the timescale on which the formation of atomic shells occurs. Analysis of the experimental data on the spontaneous fission half-lives of Rf isotopes in relation with their expected single-particle orbitals hint at a potentially abrupt decrease in half-lives of unknown neutron-deficient Rf isotopes with neutron numbers $l149$, which suggests that the isotopic border is already almost reached. However, this conjecture, which cannot be explain…