Bulletin of the American Physical Society
Fall 2022 Meeting of the APS Division of Nuclear Physics
Volume 67, Number 17
Thursday–Sunday, October 27–30, 2022; Time Zone: Central Daylight Time, USA; New Orleans, Louisiana
Session KG: Nuclear Structure V |
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Chair: Heather Crawford, Lawrence Berkeley National Laboratory Room: Hyatt Regency Hotel Celestin G |
Saturday, October 29, 2022 10:30AM - 10:42AM |
KG.00001: Investigation of States Populated in the 102Ru(p,t)100Ru Two Neutron Transfer Reaction Samantha Buck, Paul E Garrett, Vinzenz Bildstein, Christina Burbadge, Andrew D MacLean, Sally V Burbano, T. Faestermann, R. Hertenberger, H-F. Wirth, Smarajit Triambak, B Rebeiro, M Kamil, Kyle G Leach The investigation herein studies the structure of 100Ru via the two-neutron transfer reaction, 102Ru(p,t)100Ru, which was performed using the Q3D magnetic spectrograph at the Maier-Leibnitz Laboratory in Garching, Germany. The experiment employed the use of a 102Ru target which was bombarded with protons, resulting in the production of 100Ru via the pick-up of two neutrons from the target. The removal of the pair of particles from the system offers a direct study of the neutron-pair properties of the states observed in the reaction, yielding unique spin parity information and, ergo, a more robust understanding of the structure of 100Ru. The study of the excited states of 100Ru extends further in another context, as it holds the potential to bolster the understanding of the double beta decay process of 100Mo into the excited states of 100Ru. In turn, the possibility of using the decay of 100Mo as a probe for the neutrinoless double-beta-decay process is of great significance as it would shed light on the fundamental nature of neutrinos. This presentation will highlight the results from the analysis of the 102Ru(p,t)100Ru reaction, along with their significance for fundamental nuclear structure and implications pertaining to the neutrinoless double-beta-decay process. |
Saturday, October 29, 2022 10:42AM - 10:54AM |
KG.00002: High spin band structure in 61Ni Soumik Bhattacharya, Joachim Doring, Vandana Tripathi, Samuel O Ajayi, Caleb B Benetti, Lagy T Baby, Rebeka Sultana Lubna, Elizabeth Rubino, Samuel L Tabor, Yutaka Utsuno, Noritaka Shimizu, James M Allmond
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Saturday, October 29, 2022 10:54AM - 11:06AM |
KG.00003: Investigating Shape Coexistence in 100Zr Harris Bidaman, Desislava Kalaydjieva, Paul E Garrett, Magda Zielinska, Wolfram Korten, Marco Rocchini, Vinzenz Bildstein, Sangeet-Pal Pannu, Zarin Ahmed, Corina Andreoiu, D Annen, G C Ball, G Benzoni, S S Bhattacharjee, S Buck, Robin Coleman, Sophia Devinyak, Iris Dillmann, Roger Caballero-Folch, Fatima H. Garcia, Adam Garnsworthy, Beau Greaves, Christopher Griffin, Gwen F Grinyer, E Gyabeng Fuakye, Gregory Hackman, D Hymers, Rituparna Kanungo, Kushal Kapoor, Eva M Kasanda, N Marchini, K Mashtakov, A Nannini, Connor Natzke, Bruno Olaizola, Kevin Ortner, C Petrache, Marta Polettini, Allison J Radich, N. Saei, M Satrazani, Marco Siciliano, M Singh, Pietro Spagnoletti, Carl E Svensson, Diego Torres, Victoria Vedia, Rashmi Umashankar, Tammy Zidar Shape coexistence can be found in many regions of the nuclear chart and is often associated with the presence of low-lying 0+ states. In the Zr isotopes with neutron number near N=60, there is also a rapid onset of deformation of the ground state band as the neutron number is increased from 98Zr to 100Zr. In addition, multiple shapes are predicted via Monte-Carlo shell-model calculations. The spherical configuration that forms the ground state in 98Zr is predicted to migrate upwards in energy to become the 04+ state in 100Zr, while the configuration forming the deformed 02+ state in 98Zr descends in energy to become the ground state in 100Zr. In order to probe the nature of the excitations, a β decay experiment has been performed using the GRIFFIN γ ray spectrometer at the TRIUMF-ISAC facility. States populated by the decay of 100Y were investigated through γ ray spectroscopy, which includes γ-γ angular correlations to establish level spins and transition multipole mixing ratios. Lifetimes of states and conversion electron intensities were also measured using LaBr3(Ce) and Si(Li) detectors, respectively. The current status of the analysis, and the implications of the results on the structure will be discussed. |
Saturday, October 29, 2022 11:06AM - 11:18AM |
KG.00004: Nuclear moments of indium isotopes reveal abrupt change at magic number 82 Adam R Vernon, Ronald Fernando F Garcia Ruiz, Gerda Neyens, Takayuki Miyagi, Cory Binnersley, Jonathan Billowes, Kieran Flanagan, Mark L Bissell, Jeremy Bonnard, Thomas E Cocolios, Jacek Dobaczewski, Georgi Georgiev, Wouter Gins, David Leimbach, Ruben de Groote, Reinhart Hinke, Jason D Holt, Agota Koszorús, Kara Lynch, Ragnar Stroberg, Shane G Wilkins, Xiaofei Yang, Deyan Yordanov In this contribution, we present measurements of the nuclear magnetic dipole moments and nuclear electric quadrupole moments of the 113-131In isotope chain, performed using the Collinear Resonance Laser Spectroscopy experiment at ISOLDE, CERN. |
Saturday, October 29, 2022 11:18AM - 11:30AM |
KG.00005: Beta-decay study of the shape coexistence in 98Zr Konstantin Mashtakov, Paul E Garrett, Bruno Olaizola, Aaron Chester, Adam Garnsworthy, Alejandra D Varela, Alex T Laffoley, Allison J Radich, Badamsambuu Jigmeddorj, Baharak Hadinia, Balraj Singh, Carl E Svensson, Corina Andreoiu, David S Cross, Evan T Rand, Gordon C Ball, Greg A Demand, Gregory Hackman, Hillary Dawkins, Joochun Park, Jennifer L Pore, Mohamad Moukaddam, Mustafa M Rajabali, Philip J Voss, Usman Rizwan, Vinzenz Bildstein, Zhiming Wang Throughout the nuclear chart the evolution of a spherical ground-state shape into a deformed one is usually a gradual process, while in the Zr isotopic chain an abrupt shape transition is observed at N=60. This onset of deformation in 100Zr was recently reproduced in Monte Carlo Shell Model calculations [1, 2]. It was also predicted that the same deformed configuration may coexist at higher excitation energies in 98Zr isotope, which lies on the interface between spherical and deformed nuclear phases. While both theory and experiment [3,4,5,6] demonstrate a good overall description of the structure of the 98Zr, the interpretation of the higher-lying shape coexisting bands is still uncertain. Thus, a β-decay experiment was performed at TRIUMF-ISAC facility using the 8π spectrometer with β-particle detectors to measure the branching and multipolarity mixing ratios for the transitions in 98Zr. The data obtained with this setup allowed for the determination of branching ratios for very weak transitions important for assigning band structures. Furthermore, γ-γ angular correlation measurements enabled both spin assignments and mixing ratio determinations. The new results will be presented and discussed in relation to both the MCSM and recent IBM configuration mixing calculations.
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Saturday, October 29, 2022 11:30AM - 11:42AM |
KG.00006: Structure of 126,128Xe studied by Coulomb excitation Stanimir P Kisyov, C. Y. Wu, J. Henderson The electromagnetic characteristics and structure of 126,128Xe were studied by sub-barrier Coulomb excitation measurements performed at NSCL, MSU. Scattered nuclei and de-excitation gamma-rays were detected using the JANUS setup. Transition and diagonal matrix elements were determined from the experimental data using the GOSIA code. Experimental transition probabilities and quadrupole moments were compared to large-scale PMMU shell model calculations and phenomenological asymmetric rotor predictions. Quadrupole shape parameters were determined in a model-independent way. The results point out deviations from the O(6)-like structure in the ground state bands of both nuclei. The experimental data suggest near-zero quadrupole moment of the 2+2 states, different from the higher-magnitude quadrupole moments of the 2+1 states in 126,128Xe. |
Saturday, October 29, 2022 11:42AM - 11:54AM |
KG.00007: Evidence of non-statistical neutron emission following beta-decay near doubly magic 132Sn Robert Grzywacz, Joseph Heideman, Miguel Madurga, Zhengyu Xu, Toshihiko Kawano, Jutta E Escher, Tobias King, Razvan Lica It assumed that beta-delayed neutron emission proceeds statistically through the intermediate compound nucleus stage. Neutron emission probabilities from unbound states in 134Sn to known low-lying, single-particle states in 133Sn were measured. Detailed analysis of the neutron-emission branching ratios revealed discrepancies between the statistical model description and data. Our results suggest that a possible violation of the compound nucleus assumption may occur in beta-delayed neutron emission in nearly doubly-magic nuclei. This impacts the neutron emission probabilities and other properties of nuclei participating in the r-process. We propose a revised model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects using the doorway state concept. |
Saturday, October 29, 2022 11:54AM - 12:06PM |
KG.00008: First results from CLARION2-TRINITY: Coulomb Excitation of 49Ti and Emerging Collectivity Timothy Gray, James M Allmond, Andrew E Stuchbery, Angela Gargano, John L Wood, Toby King, Charlie C Rasco, Darryl Dowling, Samuel O Ajayi, Jason Aragon, Lagy T Baby, Powell Barber, Caleb B Benetti, Soumik Bhattacharya, Richard Boisseau, Alex C Conley, Chris Esparza, Jonah Gibbons, Kenneth G Hanselman, Bryan Kelly, Gordon W McCann, Ashton B Morelock, Peter DeRosa, Eilens L Saavedra, Vignesh Sitaraman, Samuel L Tabor, Eli S Temanson, Vandana Tripathi, Catur Wibisono, Ingo L Wiedenhoever, James Christie, Benjamin W Asher, Sergio Lopez-Caceres, Ram B Yadav The first results from CLARION2-TRINITY, a new charged-particle and HPGe array are presented: Coulomb excitation of 49Ti. Ti-49 can be treated as a neutron hole plus semimagic 50Ti core within the particle-core coupling scheme. Reduced electric quadrupole transition probabilities, or B(E2) strengths, for the 2+×f7/2 multiplet members and 1p-2h 3/2- cross-shell excitation were measured. The total electric quadrupole strength of 49Ti is compared to the B(E2;0+→2+) of the 50Ti core in search of enhanced quadrupole collectivity, similar to that recently observed in 129Sb relative to a 128Sn core [1]. Both cases are near double-magic nuclei and have small core B(E2) values. The results are compared to shell-model calculations with state-of-the-art nucleon-nucleon interactions. Ti-49 shows a quenching of the total quadrupole excitation strength when compared to 50Ti, in disagreement with both particle-core coupling scheme, and empirical expectations. Reasons for this reduction in E2 strength will be discussed, including cross-shell excitations and large wavefunction fragmentation. |
Saturday, October 29, 2022 12:06PM - 12:18PM |
KG.00009: Investigating the Nuclear Shell Evolution in Neutron-Rich Calcium Robin Coleman, Carl E Svensson, Corrina Andreoiu, Gordon C Ball, Soumendu S Bhattacharjee, Harris Bidaman, Vinzenz Bildstein, Samantha Buck, Grace Carpenter, Fatima H. Garcia, Adam Garnsworthy, Paul E Garrett, Christopher Griffin, Gwen F Grinyer, Madeleine Hanley, Alex T Laffoley, Rebeka Sultana Lubna, Andrew D MacLean, Matthew S Martin, Connor Natzke, Bruno Olaizola, Charlotte E Paxman, Carlotta Porzio, Allison J Radich, Marco Rocchini, Frederic Sarazin, Stephen Shadrick, S Sharma, Alireza Talebitaher, Victoria Vedia, Kenneth A Whitmore, Frank Wu, Daniel Yates, Tammy Zidar Nuclei away from the line of stability have been found to demonstrate behavior that is inconsistent with the traditional magic numbers of the spherical shell model. This has led to the concept of the evolution of nuclear shell structure in exotic nuclei, and the neutron-rich calcium isotopes are a key testing ground of these theories; there have been conflicting results from various experiments as to the true nature of a sub-shell closure for neutron-rich nuclei around 52Ca. In November of 2019, an experiment was performed at the ISAC facility of TRIUMF; 52K, 53K, and 54K were delivered to the GRIFFIN gamma-ray spectrometer paired with the SCEPTAR and the ZDS ancillary detectors for beta-tagging, as well as DESCANT for neutron-tagging. Using this powerful combination of detectors, we combine the results to construct level schemes for the isotopes populated in the beta-decay. Preliminary results from the analysis of the gamma, beta, and neutron spectra will be presented and discussed in the context of an N=32 shell closure in neutron-rich nuclei. |
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