Search results for "Acting"
showing 10 items of 338 documents
Lifetime Measurements of Excited States in Pt172 and the Variation of Quadrupole Transition Strength with Angular Momentum
2018
Lifetimes of the first excited 2(+) and 4(+) states in the extremely neutron -deficient nuclide Pt-172 have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) = 0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segre chart. The observation adds to a cluster of a few extremely neutron -deficient nuclides of the heavy transition metals with neutron numbers N approximate to 90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2: 4(1…
Dark matter searches using superheated liquids
2016
Direct detection of dark matter is one of the most important topics in modern physics. It is estimated that 22% of universe matter is composed by dark matter in front of 0.4% of ordinary matter like stars, galaxies planets and all kind of known astrophysical objects. Several kinds of experiments are nowadays involved in detection of one of the more accepted particle candidates to be dark matter: WIMPs (Weakly Interacting Massive Particles). These detectors, using several kinds of techniques: Cryogenic semiconductors, scintillation materials like I Na or noble gas chambers among others, are reporting very interesting but inconclusive results. In this paper a review of detectors that are usin…
0νββand2νββnuclear matrix elements in the interacting boson model with isospin restoration
2015
We introduce a method for isospin restoration in the calculation of nuclear matrix elements (NMEs) for $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ and $2\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$ decay within the framework of the microscopic interacting boson model (IBM-2). With this method, we calculate the NMEs for all processes of interest in $0\ensuremath{\nu}{\ensuremath{\beta}}^{\ensuremath{-}}{\ensuremath{\beta}}^{\ensuremath{-}}$ and $2\ensuremath{\nu}{\ensuremath{\beta}}^{\ensuremath{-}}{\ensuremath{\beta}}^{\ensuremath{-}}$ and in $0\ensuremath{\nu}{\ensuremath{\beta}}^{+}{\ensuremath{\beta}}^{+}$, $0\ensuremath{\nu}\mathrm{EC}{\ensuremath{\beta}}^{+}$, $R0\…
Recent results in double beta decay
2015
Abstract Nuclear matrix elements for 0νββ, 0νhββ, and 2νββ decay in the microscopic interacting boson model (IBM-2) with isospin restoration are given for all nuclei of interest from 48Ca to 238U.
Detecting filamentary pattern in the cosmic web : a catalogue of filaments for the SDSS
2014
The main feature of the spatial large-scale galaxy distribution is its intricate network of galaxy filaments. This network is spanned by the galaxy locations that can be interpreted as a three-dimensional point distribution. The global properties of the point process can be measured by different statistical methods, which, however, do not describe directly the structure elements. The morphology of the large scale structure, on the other hand, is an important property of the galaxy distribution. Here we apply an object point process with interactions (the Bisous model) to trace and extract the filamentary network in the presently largest galaxy redshift survey, the Sloan Digital Sky Survey (…
Level structure of 99Nb
1998
The β decay of 97Sr to 97Y has been investigated using ion-guide on-line mass separation and a 10 Ge-detector array to record γ−γ coincidences to a detection limit well below that of former studies. Similarities are found in the β-decay patterns of 99Zr and of its isotone 97Sr and also in the γ-ray decay rates and branchings of the corresponding levels in their respective daughters 99Nb and 97Y. This indicates a persisting influence of the d5/2 neutron shell closure for 99Nb. The level structure of 99Nb and the β-feeding pattern are discussed in the frame of the interacting boson-fermion plus broken pair model and the microscopic quasiparticle phonon model.
Possibility of a dark matter interpretation for the excess in isotropic radio emission reported by ARCADE.
2011
The ARCADE 2 Collaboration has recently measured an isotropic radio emission which is significantly brighter than the expected contributions from known extra-galactic sources. The simplest explanation of such excess involves a ``new'' population of unresolved sources which become the most numerous at very low (observationally unreached) brightness. We investigate this scenario in terms of synchrotron radiation induced by weakly interacting massive particle (WIMP) annihilations or decays in extra-galactic halos. Intriguingly, for light-mass WIMPs with a thermal annihilation cross section, the level of expected radio emission matches the ARCADE observations.
Transient behavior of a population dynamical model
2005
The transient behavior of an ecosystem with N random interacting species in the presence of a multiplicative noise is analyzed. The multiplicative noise mimics the interaction with the environment. We investigate different asymptotic dynamical regimes and the role of the external noise on the probability distribution of the local field.
Magnification of the retinal image through an intraocular Galilean telescope
2010
The intraocular Galilean telescope is a good solution for incrementing the visual capabilities of patients with age-related macular degeneration. Nevertheless, some problems arise with the use of the intraocular telescopes available at present; these problems are originated by two main factors: the use of the same power values for the lenses in all types of eyes and the fact that the values of the distance between lenses into the eye are not the most suitable ones. As a result, a high residual refraction is produced in many implanted eyes. We propose a method for predicting outcomes in order to select patients for this technique and, moreover, for choosing the optimum power for the positive…
Role of Single-Particle Energies in Microscopic Interacting Boson Model Double Beta Decay Calculations
2021
Single-particle level energies form a significant input in nuclear physics calculations where single-particle degrees of freedom are taken into account, including microscopic interacting boson model investigations. The single-particle energies may be treated as input parameters that are fitted to reach an optimal fit to the data. Alternatively, they can be calculated using a mean field potential, or they can be extracted from available experimental data, as is done in the current study. The role of single-particle level energies in the microscopic interacting boson model calculations is discussed with special emphasis on recent double beta decay calculations.