Showing papers by "R. Wadsworth published in 2021"
Spanish National Research Council1, University of Tokyo2, Université Paris-Saclay3, University of Giessen4, Hungarian Academy of Sciences5, University of Bordeaux6, Istituto Nazionale di Fisica Nucleare7, University of York8, Technische Universität München9, Autonomous University of Madrid10, University of Oslo11
TL;DR: In this paper, the authors studied the proton-rich T = 1 nucleus through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0+}→2^{+}), which is the first violation of isospin symmetry at this level observed in the transition matrix elements.
Abstract: We studied the proton-rich T_{z}=-1 nucleus ^{70}Kr through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0^{+}→2^{+}). Comparison with the other members of the A=70 isospin triplet, ^{70}Br and ^{70}Se, studied in the same experiment, shows a 3σ deviation from the expected linearity of the electromagnetic matrix elements as a function of T_{z}. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei ^{70}Kr and ^{70}Se contrary to the model predictions.
11 citations
11 Jan 2021-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: Using the coincident γ -rays from agata, the performances of the Artificial Neural Networks as classifiers are measured and compared on real data and differences, in particular related to the computing times, have been highlighted.
Abstract: Three different Artificial Neural Network architectures have been applied to perform neutron/ γ discrimination in neda based on waveform and time-of-flight information. Using the coincident γ -rays from agata , we have been able to measure and compare on real data the performances of the Artificial Neural Networks as classifiers. While the general performances are quite similar for the data set we used, differences, in particular related to the computing times, have been highlighted. One of the Artificial Neural Network architecture has also been found more robust to time misalignment of the waveforms. Such a feature is of great interest for online processing of waveforms.
10 citations
TL;DR: In this article, the excitation-energy differences between these levels and the isobaric analogue states in the T z = + 2 mirror partner, 56Fe, are compared with large-scale shell-model calculations considering the full pf valence space and various isospin-breaking contributions.
5 citations
TL;DR: In this article, a sequence of excited states has been established for the first time in the proton-rich nucleus 48Fe (Z=26, N=22) using the technique of mirrored (i.e. analogue) one-nucleon knockout reactions.
5 citations
TL;DR: In this paper, the structure of Po-208 populated through the EC/beta(+) decay of At-208 was investigated using gamma-ray spectroscopy at the ISOLDE Decay Station.
Abstract: The structure of Po-208 populated through the EC/beta(+) decay of At-208 is investigated using gamma-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. rays which have been (re)assigned a position. The level scheme is compared to shell model calculations. Through this analysis approximately half of the beta-decay strength of At-208 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 region provides an excellent testing ground for the competition between allowed and first-forbidden beta-decay calculations, important for the detailed understanding of the nucleosynthesis of heavy elements.
4 citations
TL;DR: In this paper, the authors studied the low-lying excited states in the neutron-deficient $N=======�γεργεγεβεβδεβα+εβγγε βα+βαβαγαββατε βγαγγα+ βαταβγαα+γβααγβεγα−βασταγ βασα+αβσα−γβγββε βσαα + β
Abstract: The low-lying excited states in the neutron-deficient $N
=
Z
+
1$
nucleus
$^{87}_{43}$Tc$_{44}$
have been studied via the fusion-evaporation reaction $^{54}$Fe $(^{36}Ar, 2n1p)$ $^{87}$Tc at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt
γ
rays, neutrons, and charged particles emitted in the reaction. A level scheme of $^{87}$Tc from the $(9/2^+_{g.s})$ state to the $(
33
/
2^+_1$) state was established based on six mutually coincident
γ
-ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at $ℏω ≈ 0.50$ MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around $N=44$ is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the $N=Z$ line.
4 citations
2 citations