Search results for "DECAY"
showing 10 items of 2087 documents
Measurement of the 2νββ decay half-life and search for the 0νββ decay of 116Cd with the NEMO-3 detector
2017
The NEMO-3 experiment measured the half-life of the 2νββ decay and searched for the 0νββ decay of 116Cd. Using 410 g of 116Cd installed in the detector with an exposure of 5.26 y, (4968±74) events corresponding to the 2νββ decay of 116Cd to the ground state of 116Sn have been observed with a signal to background ratio of about 12. The half-life of the 2νββ decay has been measured to be T2ν1/2=[2.74±0.04(stat)±0.18(syst)]×1019 y. No events have been observed above the expected background while searching for 0νββ decay. The corresponding limit on the half-life is determined to be T0ν1/2≥1.0×1023 y at the 90% C.L. which corresponds to an upper limit on the effective Majorana neutrino mass of…
Measuring nuclear reaction cross sections to extract information on neutrinoless double beta decay
2017
Neutrinoless double beta decay (0v\b{eta}\b{eta}) is considered the best potential resource to access the absolute neutrino mass scale. Moreover, if observed, it will signal that neutrinos are their own anti-particles (Majorana particles). Presently, this physics case is one of the most important research "beyond Standard Model" and might guide the way towards a Grand Unified Theory of fundamental interactions. Since the 0v\b{eta}\b{eta} decay process involves nuclei, its analysis necessarily implies nuclear structure issues. In the NURE project, supported by a Starting Grant of the European Research Council (ERC), nuclear reactions of double charge-exchange (DCE) are used as a tool to extr…
Charge-exchange reactions on double-β decaying nuclei populating Jπ=2− states
2017
The (3He,t) charge-exchange reaction populating Jπ=2− states has been examined at 420 MeV incident energy for a series of double-β decaying nuclei, i.e., 76Ge, 82Se, 96Zr, 100Mo, 128Te, 130Te, and 136Xe. The measurements were carried out at the Grand Raiden spectrometer of the Research Center for Nuclear Physics at the University Osaka with typical spectral resolution of 30–40 keV. It is found that the charge-exchange reaction leading to 2− spin-dipole states is selective to the στ part of the interaction much similar to the observed selectivity to Gamow-Teller transitions. In the present case, the ΔL=1 peak cross sections at finite momentum transfers are used to extract the spin-isospin pa…
Two-neutrino ββ decays and low-lying Gamow-Teller β− strength functions in the mass range A=70–176
2017
We apply the proton-neutron deformed quasiparticle random-phase approximation (pn-dQRPA) to describe the low-lying (E 6 MeV) 1+ Gamow-Teller (GT) strength functions in odd-odd deformed nuclei which participate as intermediate nuclei in two-neutrino double-β-decay (2νββ) transitions within the mass range A = 70–176. In deriving equations of motion we use a single-particle basis with projected angular momentum, provided by the diagonalization of a spherical mean field furnished with a quadrupole-quadrupole interaction. The schematic residual Hamiltonian contains pairing and proton-neutron interaction terms in particle-hole (ph) and particle-particle (pp) channels, with constant strengths. By …
Hydrolate and EO Application to Reduce Decay of Carica papaya during Storage
2023
Postharvest fruit loss is caused by the absence of advanced handling and storage technologies and the quiescent presence of fungal pathogens. Therefore, there is a growing demand for sustainable decisions for the planet. This study focused on the use of two types of edible coatings: one was based on the essential oil of Origanum vulgare L. subsp. viridulum with Aloe arborescens Mill. gel (EC1), and the other was based on the hydrolate only (EC2). These treatments were applied to provide defense against fungal infections in papaya (Carica papaya L. cv Solo), and the storage time was 25 days (T5 ± 1 °C). Fruits coated with EC1 were more contaminated with fungal pathogens than both control (CT…
Mössbauer Emission Spectroscopy of Mixed-Valency after Nuclear Decay in Iron Complexes
1991
The population of anomalous spin states and aliovalent charge states of iron induced by the 57 Co(EC)57 Fe nuclear decay in polycristalline transition metal compounds was studied by means of Coincidence Mossbauer Emission Spectroscopy (CMES), that is Time-Differential Mossbauer Emission Spectroscopy (TDMES) as well as γ/Xray-Coincidence Mossbauer Emission Spectroscopy (γ/X-CMES). By use of time-integral Mossbauer emission spectroscopy (TIMES) we have observed anomalous high spin (S = 2) states of 57 Fe(II) in the system [57Co/Co(phen)3(ClO 4)2 with increasing intensities on lowering the temperature. With TDMES we followed quantitatively the high spin-low spin relaxation kinetics in this com…
Steering Distillation Processes through Zeno dynamics
2005
A quantum system in interaction with a repeatedly measured one undergoes a nonunitary time evolution and is pushed into a subspace substantially determined by the two-system coupling. The possibility of suitably modifying such an evolution through quantum Zeno dynamics (i.e., the generalized quantum Zeno effect) addressing the system toward an a priori decided target subspace is illustrated. Applications and their possible realizations in the context of trapped ions are also discussed.
β-decay rates of 115,117Rh into 115,117Pd isotopes in the microscopic interacting boson-fermion model
2020
The structure of odd-A 115,117Rh and 115,117Pd isotopes is studied by means of the neutron-proton interacting boson-fermion model (IBFM-2). JP=12+ quantum number assignment for the 115,117Pd ground states is critically discussed and the predicted energy levels are compared to the existing experimental data. The resulting nuclear wave functions are used to compute the β-decay ft values of the transitions from 115,117Rh to 115,117Pd in the microscopic IBFM-2 and the results compared with the data. peerReviewed
Restoring the valence-shell stabilization in 140Nd
2020
A projectile Coulomb-excitation experiment was performed at the radioactive-ion beam facility HIE-ISOLDE at CERN to obtain $E2$ and $M1$ transition matrix elements of $^{140}$Nd using the multistep Coulomb-excitation code GOSIA. The absolute $M1$ strengths, $\textrm{B}(M1;2^+_2→2^+_1)=0.033(8)μ^2_N,\textrm{B}(M1;2^+_3→2^+_1)=0.26^{+0.11}_{−0.10}μ^2_N$, and $\textrm{B}(M1;2^+_4→2^+_1)<0.04μ^2_{\textrm{N}}$, identify the $2^+_3$ state as the main fragment of the one-quadrupole-phonon proton-neutron mixed-symmetry state of $^{140}$Nd. The degree of F-spin mixing in $^{140}$Nd was quantified with the determination of the mixing matrix element $V_{\textrm{F−mix}}<7^{+13}_{−7}$keV.
Competition between allowed and first-forbidden β decays of At208 and expansion of the Po208 level scheme
2021
The structure of 208Po populated through the EC/β+ decay of 208At is investigated using γ-ray spectroscopy at the ISOLDE Decay Station. The presented level scheme contains 27 new excited states and 43 new transitions, as well as a further 50 previously observed γ rays which have been (re)assigned a position. The level scheme is compared to shell model calculations. Through this analysis approximately half of the β-decay strength of 208At is found to proceed via allowed decay and half via first-forbidden decay. The first-forbidden transitions predominantly populate core excited states at high excitation energies, which is qualitatively understood using shell model considerations. This mass r…