A5059201838- Nuclear physics research studies
- Astronomical and nuclear sciences
- Nuclear Physics and Applications
- Atomic and Molecular Physics
- Advanced NMR Techniques and Applications
- Quantum Chromodynamics and Particle Interactions
- Advanced Chemical Physics Studies
- Rare-earth and actinide compounds
- Particle physics theoretical and experimental studies
- Radiation Detection and Scintillator Technologies
- Particle Detector Development and Performance
- Neutrino Physics Research
- Astro and Planetary Science
- Nuclear reactor physics and engineering
- Quantum, superfluid, helium dynamics
- Radioactive Decay and Measurement Techniques
- Atomic and Subatomic Physics Research
- Scientific Research and Discoveries
- Radioactivity and Radon Measurements
- Crystallography and Radiation Phenomena
- Statistical Distribution Estimation and Applications
- Particle Accelerators and Free-Electron Lasers
- Muon and positron interactions and applications
- Innovation, Technology, and Society
- Quantum chaos and dynamical systems
Michigan State University
2018-2025
Facility for Rare Isotope Beams
2025
Florida State University
2020-2024
University of Cologne
2012-2023
National Superconducting Cyclotron Laboratory
2018-2023
University of Florida
2023
University of the Witwatersrand
2021
We introduce a new method for the study of fluctuations partial transition widths based on nuclear resonance fluorescence experiments with quasimonochromatic linearly-polarized photon beams below particle separation thresholds. It is average branching decays $J=1$ states an even-even nucleus to $2^+_1$ state in comparison ground state. Between 5 and 7 MeV, almost constant ratio 0.490(16) observed nuclide $^{150}$Nd. Assuming $\chi^2$-distributed widths, this related degree freedom $\nu =...
The experimental $E1$ strength distribution below 4 MeV in rare-earth nuclei suggests a local breaking of isospin symmetry. In addition to the octupole states, additional ${J}^{\ensuremath{\pi}}={1}^{\ensuremath{-}}$ states with enhanced have been observed by means ($\ensuremath{\gamma}$,$\ensuremath{\gamma}$\ensuremath{'}) experiments. By reproducing results, $spdf$ interacting boson model calculations provide further evidence for formation an $\ensuremath{\alpha}$ cluster medium-mass and...
Partial cross sections of the $^{89}$Y(p,$\gamma$)$^{90}$Zr reaction have been measured to investigate $\gamma$-ray strength function in neutron-magic nucleus $^{90}$Zr. For five proton energies between $E_p=3.65$ MeV and $E_p=4.70$ MeV, partial for population seven discrete states $^{90}$Zr determined by means in-beam spectroscopy. Since these transitions are dominantly $E1$ character, present measurement allows an access low-lying dipole A based on experimental data could be extracted,...
Background: Selenium and germanium nuclei are associated with both triaxiality shape coexistence. The relative influence of these deformation effects on the low-lying nuclear structure remains subject much discussion additional attention drawn to $^{76}\mathrm{Se}$ $^{76}\mathrm{Ge}$ due potential for observation neutrinoless double-$\ensuremath{\beta}$ decay.Purpose: Experimental observables related lacking in precision. purpose present paper is provide electric quadrupole matrix elements...
We present an extensive experimental study of the recently predicted pygmy quadrupole resonance (PQR) in Sn isotopes, where complementary probes were used. In this study, (α,α′γ) and (γ,γ′) experiments performed on 124Sn. both reactions, Jπ=2+ states below excitation energy 5 MeV populated. The E2 strength integrated over full transition densities could be extracted from experiment, while experiment at chosen kinematics strongly favors surface modes because strong α-particle absorption...
We report on the first (p,p′γ) experiments at Ep=80 MeV to investigate Pygmy Dipole Resonance (PDR) in semi-magic nucleus 140Ce. This experiment is latest a series of PDR with different complementary probes provide multi-messenger data set properties In addition, calculations within Quasi-particle Phonon Model (QPM) have been performed. Cross sections calculated for proton- as well α-scattering reactions based transition densities obtained from QPM, not only RPA level, but including full...
In the Ge-Sr mass region, isotopes with neutron number $N \leq 40$ are known to feature rapid shape changes both nucleon and angular momentum. To gain new insights into their structure, inelastic proton scattering experiments in inverse kinematics were performed on rare $^{74,76}$Kr. This work focuses observables related $J^{\pi} = 4^+_1$ states of Kr and, particular, hexadecapole degree freedom. By performing coupled-channels calculations, deformation parameters $\beta_4$ determined for...
We performed a measurement of the $^{51}\mathrm{V}(d,p)^{52}\mathrm{V}$ reaction at 16 MeV using Florida State University Super-Enge Split-Pole Spectrograph (SE-SPS) to search for single-neutron transfer strength ${g}_{9/2}$ intruder orbit. Measurements $\ensuremath{\nu}{g}_{9/2}$ with ($d,p$) reactions in $N=29$ isotones $^{49}\mathrm{Ca}, ^{51}\mathrm{Ti}, ^{53}\mathrm{Cr}$, and $^{55}\mathrm{Fe}$ have concluded that much expected is ``missing''; is, summed smaller than sum rule. In...
$J^{\pi}$= 0$^+$ states have been investigated in the actinide nucleus ${}^{240}$Pu up to an excitation energy of 3 MeV with a high-resolution (p,t) experiment at $E_{p}$= 24 MeV. To test recently proposed 0$^+_2$ double-octupole structure, phenomenological approach spdf-interacting boson model has chosen. In addition, total strength distribution and $0^+$ fragmentation compared predictions as well previously studied reactions actinides. The results suggest that structure actinides might be...
New experimental data on the neutron single-particle character of Pygmy Dipole Resonance (PDR) in ^{208}Pb are presented. They were obtained from (d,p) and resonant proton scattering experiments performed at Q3D spectrograph Maier-Leibnitz Laboratory Garching, Germany. The new compared to large suite complementary, available for establish as an additional, valuable, probe study PDR its collectivity. Besides states, different features strength distributions discussed large-scale shell model...
The neutron-rich nuclei in the $N=28$ island of inversion have attracted considerable experimental and theoretical attention, providing great insight into evolution shell structure nuclear shape exotic nuclei. In this work, for first time, quadrupole collectivity is assessed simultaneously on top $3/{2}^{\ensuremath{-}}$ ground state $7/{2}^{\ensuremath{-}}$ shape-coexisting isomer $^{43}\mathrm{S}$, putting unique interpretation configuration coexistence at $N=27$ 28 sulfur isotopic chain...
The microscopic structure of the low-energy electric dipole response, commonly denoted as pygmy resonance (PDR), was studied for ^{120}Sn in a ^{119}Sn(d,pγ)^{120}Sn experiment. Unprecedented access to single-particle excited 1^{-} states below and around neutron-separation threshold obtained by comparing experimental data predictions from novel theoretical approach. approach combines detailed input energy-density functional plus quasiparticle-phonon model theory with reaction obtain...
Nucleon transfer reactions are sensitive nuclear structure probes. The authors used ultrahigh-resolution two-nucleon ($p$,$t$) to identify 15 new excited ${0}^{+}$ states of ${}^{240}$Pu, some 7 times the number previously known, plus other also seen for first time. These data, combined with existing $\ensuremath{\gamma}$-ray data and model calculations, provide information on pairing correlations two-phonon octupole excitations in difficult-to-investigate actinide nuclei.
Simpson and Tostevin proposed that the width shape of exclusive parallel momentum distributions $A\ensuremath{-}2$ residue in direct two-nucleon knockout reactions carry a measurable sensitivity to nucleon single-particle configurations their couplings within wave functions exotic nuclei. We report here on first benchmarks use this new spectroscopic tool. Exclusive for states neutron-deficient nuclei $^{22}\mathrm{Mg},^{23}\mathrm{Al}$, $^{24}\mathrm{Si}$ populated such two-neutron removal...
Background: The semimagic Sn ($Z=50$) isotopes have been subject to many nuclear-structure studies. Signatures of shape coexistence observed and attributed two-proton--two-hole (2p-2h) excitations across the $Z=50$ shell closure. In addition, low-lying features which effectively constrained theoretical models in past. One example are so-called quadrupole-octupole coupled states (QOC) caused by coupling collective quadrupole octupole phonons.Purpose: Proton-scattering experiments followed...
Background: Reaction rates of radiative capture reactions can play a crucial role in the nucleosynthesis heavy nuclei explosive stellar environments. These reaction depend strongly on $\ensuremath{\gamma}$-ray decay widths products, which are, for nonresonant at high excitation energies, derived from strength function and nuclear level density. Recently, ratio method was applied to primary $\ensuremath{\gamma}$ rays observed ($d,p$) resonance fluorescence measurements extract dipole atomic...
The degree of collectivity the Pygmy Dipole Resonance (PDR) is an open question. Recently, Ries {\it et al.} have suggested onset PDR beyond $N=28$ based on observation a significant $E1$ strength increase in Cr isotopes and proposed that has its origin few-nucleon effect. Earlier, Inakura had predicted by performing systematic calculations using random-phase approximation (RPA) with Skyrme functional SkM* strongly depends position Fermi level it displays clear correlation occupation orbits...
Production cross sections were measured for fragments produced by an 85 MeV/u Pt198 beam incident on a beryllium target. Event-by-event particle identification of A, Z, and q the reaction products was performed employing energy loss, time-of-flight, magnetic rigidity, total kinetic measurements. Over 70 nuclei in Hf-Pt region identified, including three isotopes first observed this work: Hf191,192 Lu189. Due to existence multiple charge states between H-like C-like ions, new analysis method...
Background: Excitations with mixed proton-neutron symmetry have been previously observed in the $N=52$ isotones. Besides well established quadrupole mixed-symmetry states (MSS), octupole and hexadecapole MSS recently proposed for nuclei $^{92}$Zr $^{94}$Mo. Purpose: The heaviest stable isotone $^{96}$Ru was investigated to study evolution of increasing proton number. Methods: Two inelastic proton-scattering experiments on were performed extract branching ratios, multipole mixing level...
Neutron-deficient selenium isotopes are thought to undergo a rapid shape change from prolate deformation near the line of beta stability towards oblate around $N=Z$. The point at which this occurs is unknown, with inconsistent predictions available theoretical models. A common feature in models delicate nature transition, introduction even modest spin system sufficient ordering and configurations. We present measurement quadrupole moment first-excited state radioactive $^{72}\mathrm{Se}$---a...
Background: In the $A\ensuremath{\approx}50$ mass region $M1$ spin-flip transitions are prominent around 9 MeV. An accumulation of ${1}^{\ensuremath{-}}$ states between 5 and 8 MeV generating additional $E1$ strength, also denoted as pygmy dipole resonance, has been established in many nuclei with neutron excess within last decade.Purpose: The $\ensuremath{\gamma}$-decay behavior $J=1$ investigated an NRF experiment. excitations have compared to shell model calculations.Methods: were excited...
The half-life of the ${4}_{2}^{+}$ state $2\mathrm{p}\ensuremath{-}2\mathrm{h}$ proton intruder band $^{116}\mathrm{Sn}$ has been measured with fast-timing technique. lifetime ${T}_{1/2}=29(10)$ ps leads to a transition probability $B\left(E2;{4}_{2}^{+}\ensuremath{\rightarrow}{2}_{2}^{+}\right)=40(13)$ Weisskopf units, which is in very good agreement large $B\left(E2;{2}_{2}^{+}\ensuremath{\rightarrow}{0}_{3}^{+}\right)$ value previously and provides strong support for ${0}_{3}^{+}$ as...