Search results for "Fysiikka"
showing 10 items of 1348 documents
Neutron excitations in 119Ba
2021
The neutron-deficient 119Ba nucleus has been studied using the 58Ni(64Zn,2pn) reaction and the JUROGAM 3 γ-ray detector array coupled to the MARA recoil-mass separator setup. One new rotational band and several low-lying states are newly identified. A half-life of T1/2=0.36(2)μs has been measured for the 5/2− bandhead of the νh11/2 band. The two previously known rotational bands are confirmed, except for the higher part of the +1/2 signature partner of the positive-parity band. Configurations are assigned based on the analysis of the observed quasiparticle alignments whose nature is unveiled by the calculations using the particle number conserving cranked shell model. peerReviewed
First Evidence of Axial Shape Asymmetry and Configuration Coexistence in 74Zn : Suggestion for a Northern Extension of the N = 40 Island of Inversion
2023
The excited states of N=44 74Zn were investigated via γ-ray spectroscopy following 74Cu β decay. By exploiting γ−γ angular correlation analysis, the 2+2, 3+1, 0+2, and 2+3 states in 74Zn were firmly established. The γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2+2, 3+1, and 2+3 states were measured, allowing for the extraction of relative B(E2) values. In particular, the 2+3→0+2 and 2+3→4+1 transitions were observed for the first time. The results show excellent agreement with new microscopic large-scale shell-model calculations, and are discussed in terms of underlying shapes, as well as the role of neutron excitations across the N=40 gap. Enhanced axial shape asy…
New measurement of double-β decays of 100Mo to excited states of 100Ru with the CUPID-Mo experiment
2023
The CUPID-Mo experiment, located at the Laboratoire Souterrain de Modane (France), was a demonstrator experiment for CUPID. It consisted of an array of 20Li2100MoO4 (LMO) calorimeters, each equipped with a Ge light detector for particle identification. In this work, we present the result of a search for two-neutrino and neutrinoless double-β decays of 100Mo to the first 0+ and 2+ excited states of 100Ru using the full CUPID-Mo exposure (2.71kgyr of LMO). We measure the half-life of 2νββ decay to the 0+1 state as T2ν→0+11/2=(7.5±0.8(stat.)+0.4−0.3(syst.))×1020yr. The bolometric technique enables measurement of the electron energies as well as the γ rays from nuclear deexcitation and this all…
Intruder features in the island of inversion : The 33Mg case
2001
The 33 Na β decay was studied online using mass separation techniques and a first description of the level structure of the neutron-rich isotope 33 Mg , with N = 21 , has been obtained. The experiment involved the measurement of β-γ, β-γ-γ, and β − n − γ coincidences as well as neutron spectra by time-of-flight technique. The first low energy level scheme for the daughter nucleus 33 Mg is given with five bound states. Spin and parity assignments are proposed according to β feedings and γ-ray multipolarities. β-strength distribution is evaluated, taking into account 1 n - and 2 n -emission channels and it is compared with the calculated GT strength distribution. In particular, the 1 p − 1 h …
Decay spectroscopy of heavy nuclei beyond the proton drip line
2003
Determining gA/gV with High-Resolution Spectral Measurements Using a LiInSe2 Bolometer
2022
Neutrinoless double beta decay (0νββ) processes sample a wide range of intermediate forbidden nuclear transitions, which may be impacted by quenching of the axial vector coupling constant (gA/gV), the uncertainty of which plays a pivotal role in determining the sensitivity reach of 0νββ experiments. In this Letter, we present measurements performed on a high-resolution LiInSe2 bolometer in a “source = detector” configuration to measure the spectral shape of the fourfold forbidden β decay of 115In. The value of gA/gV is determined by comparing the spectral shape of theoretical predictions to the experimental β spectrum taking into account various simulated background components as well as a …
Spectroscopy along flerovium decay chains. III : Details on experiment, analysis, 282Cn, and spontaneous fission branches
2023
Flerovium isotopes (element Z=114) were produced in the fusion-evaporation reactions 48Ca+242,244Pu and studied with an upgraded TASISpec decay station placed in the focal plane of the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Germany. Twenty-nine flerovium decay chains were identified by means of correlated implantation, α decay, and spontaneous fission events. Data analysis aspects and statistical assessments, primarily based on measured rates of various events, which laid the foundation for the comprehensive spectroscopic information on the flerovium decay chains, are presented in detail. Various decay scenarios of an excited state obse…
Investigation of K+K− interactions via femtoscopy in Pb-Pb collisions at √sNN = 2.76 TeV at the CERN Large Hadron Collider
2023
Femtoscopic correlations of nonidentical charged kaons (K+K−) are studied in Pb-Pb collisions at a center-of-mass energy per nucleon-nucleon collision √sNN=2.76 TeV by ALICE at the CERN Large Hadron Collider. One-dimensional K+K− correlation functions are analyzed in three centrality classes and eight intervals of particle-pair transverse momentum. The Lednický and Luboshitz interaction model used in the K+K− analysis includes the final-state Coulomb interactions between kaons and the final-state interaction through a0(980) and f0(980) resonances. The mass of f0(980) and coupling were extracted from the fit to K+K− correlation functions using the femtoscopic technique. The measured mass and…
113Cdβ-decay spectrum and gA quenching using spectral moments
2023
We present an alternative analysis of the 113Cdβ-decay electron energy spectrum in terms of spectral moments μn, corresponding to the averaged values of nth powers of the β particle energy. The zeroth moment μ0 is related to the decay rate, while higher moments μn are related to the spectrum shape. The here advocated spectral-moment method (SMM) allows for a complementary understanding of previous results, obtained using the so-called spectrum-shape method (SSM) and its revised version, in terms of two free parameters: r=gA/gV (the ratio of axial-vector to vector couplings) and s (the small vectorlike relativistic nuclear matrix element, s-NME). We present numerical results for three differ…