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40 results on '"Hoff, D. E. M."'

1. Investigating the effects of precise mass measurements of Ru and Pd isotopes on machine learning mass modeling

Author

Porter, W. S., Liu, B., Ray, D., Valverde, A. A., Li, M., Mumpower, M. R., Brodeur, M., Burdette, D. P., Callahan, N., Cannon, A., Clark, J. A., Hoff, D. E. M., Houff, A. M., Kondev, F. G., Lovell, A. E., Mohan, A. T., Morgan, G. E., Quick, C., Savard, G., Sharma, K. S., Sprouse, T. M., and Varriano, L.

Subjects
Nuclear Experiment
Abstract

Atomic masses are a foundational quantity in our understanding of nuclear structure, astrophysics and fundamental symmetries. The long-standing goal of creating a predictive global model for the binding energy of a nucleus remains a significant challenge, however, and prompts the need for precise measurements of atomic masses to serve as anchor points for model developments. We present precise mass measurements of neutron-rich Ru and Pd isotopes performed at the Californium Rare Isotope Breeder Upgrade facility at Argonne National Laboratory using the Canadian Penning Trap mass spectrometer. The masses of $^{108}$Ru, $^{110}$Ru and $^{116}$Pd were measured to a relative mass precision $\delta m/m \approx 10^{-8}$ via the phase-imaging ion-cyclotron-resonance technique, and represent an improvement of approximately an order of magnitude over previous measurements. These mass data were used in conjunction with the physically interpretable machine learning (PIML) model, which uses a mixture density neural network to model mass excesses via a mixture of Gaussian distributions. The effects of our new mass data on a Bayesian-updating of a PIML model are presented., Comment: 6 pages, 4 figures

Published
2024
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2. Precise Mass Measurements of $A=133$ Isobars with the Canadian Penning Trap: Resolving the $Q_{\beta^-}$ anomaly at $^{133}$Te

Author

Valverde, A. A., Kondev, F. G., Liu, B., Ray, D., Brodeur, M., Burdette, D. P., Callahan, N., Cannon, A., Clark, J. A., Hoff, D. E. M., Orford, R., Porter, W. S., Sharma, K. S., and Varriano, L.

Subjects
Nuclear Experiment
Abstract

We report precision mass measurements of $^{133}$Sb, $^{133g,m}$Te, and $^{133g,m}$I, produced at CARIBU at Argonne National Laboratory's ATLAS facility and measured using the Canadian Penning Trap mass spectrometer. These masses clarify an anomaly in the $^{133}$Te $\beta$-decay. The masses reported in the 2020 Atomic Mass Evaluation (M. Wang et al., 2021) produce $Q_{\beta^-}(^{133}$Te)=2920(6) keV; however, the highest-lying $^{133}$I level populated in this decay is observed at $E_i=2935.83(15)$ keV, resulting in an anomalous $Q_{\beta^{-}}^{i}=-16(6)$~keV. Our new measurements give $Q_{\beta^-}(^{133}\text{Te})=2934.8(11)$ keV, a factor of five more precise, yielding $Q{_\beta^i}=-1.0(12)$~keV, a 3$\sigma$ shift from the previous results. This resolves this anomaly, but indicates further anomalies in our understanding of the structure of this isotope., Comment: 5 pages, 3 figures

Published
2023
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3. Strong evidence for 9N and the limits of existence of atomic nuclei

Author

Charity, R. J., Wylie, J., Wang, S. M., Webb, T. B., Brown, K. W., Cerizza, G., Chajecki, Z., Elson, J. M., Estee, J., Hoff, D. E. M, Kuvin, S. A., Lynch, W. G., Manfredi, J., Michel, N., McNeel, D. G., Morfouace, P., Nazarewicz, W., Pruitt, C. D., Santamaria, C., Sweany, S., Smith, J., Sobotka, L. G., Tsang, M. B., and Wuosmaa, A. H.

Subjects
Nuclear Experiment
Abstract

The boundaries of the Chart of Nuclides contain exotic isotopes that possess extreme proton-toneutron asymmetries. Here we report on strong evidence of 9N, one of the most exotic proton-rich isotopes where more than one half of its constitute nucleons are unbound. With seven protons and two neutrons, this extremely proton-rich system would represent the first-known example of a ground-state five-proton emitter. The invariant-mass spectrum of its decay products can be fit with two peaks whose energies are consistent with the theoretical predictions of an open-quantum-system approach, however we cannot rule out the possibility that only a single resonance-like peak is present in the spectrum., Comment: 4 figures, 7pages

Published
2023

4. Experimental Study of the $^{\textbf{38}}$S Excited Level Scheme

Author

Hoffman, C. R., Lubna, R. S., Rubino, E., Tabor, S. L., Auranen, K., Bender, P. C., Campbell, C. M., Carpenter, M. P., Chen, J., Gott, M., Greene, J. P., Hoff, D. E. M., Huang, T., Iwasaki, H., Kondev, F. G., Lauritsen, T., Longfellow, B., Santamaria, C., Seweryniak, D., Tang, T. L., Wilson, G. L., Wu, J., and Zhu, S.

Subjects
Nuclear Experiment
Abstract

Information on the $^{38}$S level scheme was expanded through experimental work utilizing a fusion-evaporation reaction and in-beam $\gamma$-ray spectroscopy. Prompt $\gamma$-ray transitions were detected by the Gamma-Ray Energy Tracking Array (GRETINA) and recoiling $^{38}$S residues were selected by the Fragment Mass Analayzer (FMA). Tools based on machine-learning techniques were developed and deployed for the first time in order to enhance the unique selection of $^{38}$S residues and identify any associated $\gamma$-ray transitions. The new level information, including the extension of the even-spin yrast sequence through $J^{\pi} = 8^{(+)}$, was interpreted in terms of a basic single-particle picture as well shell-model calculations which incorporated the empirically derived FSU interaction. A comparison between the properties of the yrast states in the even-$Z$ $N=22$ isotones from $Z=14$ to $20$, and for $^{36}$Si-$^{38}$S in particular, was also presented with an emphasis on the role and influence of the neutron $1p_{3/2}$ orbital on the structure in the region.

Published
2023
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5. $^{57}$Zn $\beta$-delayed proton emission establishes the $^{56}$Ni $rp$-process waiting point bypass

Author

Saxena, M., Ong, W. -J, Meisel, Z., Hoff, D. E. M., Smirnova, N., Bender, P. C., Burcher, S. P., Carpenter, M. P., Carroll, J. J., Chester, A., Chiara, C. J., Conaway, R., Copp, P. A., Crider, B. P., Derkin, J., Estrade, A., Hamad, G., Harke, J. T., Jain, R., Jayatissa, H., Liddick, S. N., Longfellow, B., Mogannam, M., Montes, F., Nepal, N., Ogunbeku, T. H., Richard, A. L., Schatz, H., Soltesz, D., Subedi, S. K., Sultana, I., Tamashiro, A. S., Tripathi, V., Xiaog, Y., and Zink, R.

Subjects
Nuclear Experiment, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

We measured the $^{57}$Zn $\beta$-delayed proton ($\beta$p) and $\gamma$ emission at the National Superconducting Cyclotron Laboratory. We find a $^{57}$Zn half-life of 43.6 $\pm$ 0.2 ms, $\beta$p branching ratio of (84.7 $\pm$ 1.4)%, and identify four transitions corresponding to the exotic $\beta$-$\gamma$-$p$ decay mode, the second such identification in the $f p$-shell. The $p/\gamma$ ratio was used to correct for isospin mixing while determining the $^{57}$Zn mass via the isobaric multiplet mass equation. Previously, it was uncertain as to whether the rp-process flow could bypass the textbook waiting point $^{56}$Ni for astrophysical conditions relevant to Type-I X-ray bursts. Our results definitively establish the existence of the $^{56}$Ni bypass, with 14-17% of the $rp$-process flow taking this route.

Published
2022
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6. Using spin alignment of inelastically-excited fast beams to make spin assignments: the spectroscopy of 13O as a test case

Author

Charity, R. J., Webb, T. B., Elson, J. M., Hoff, D. E. M., Pruitt, C. D., Sobotka, L. G., Navratil, P., Hupin, G., Kravvaris, K., Quaglioni, S., Brown, K. W., Cerizza, G., Estee, J., Lynch, W. G., Manfredi, J., Morfouace, P., Santamaria, C., Sweany, S., Tsang, M. B., Tsang, T., Zhu, K., Kuvin, S. A., McNeel, D., Smith, J., Wousmaa, A. H., and Chajecki, Z.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

Excited states in 13O were investigated using inelastic scattering of an E/A=69.5-MeV 13O beam off of a 9Be target. The excited states were identified in the invariant-mass spectra of the decay products. Both single proton and sequential two-proton decays of the excited states were examined. For a number of the excited states, the protons were emitted with strong anisotropy where emissions transverse to the beam axis are favored. The measured proton-decay angular distributions were compared to predictions from distorted-wave born-approximation (DWBA) calculations of the spin alignment which was shown to be largely independent of the excitation mechanism. The deduced $^{13}$O level scheme is compared to ab initio no-core shell model with continuum (NCSMC) predictions. The lowest-energy excited states decay isotropically consistent with predictions of strong proton 1s1/2 structure. Above these states in the level scheme, we observed a number of higher-spin states not predicted within the model. Possibly these are associated with rotational bands built on deformed cluster configurations predicted by antisymmetrized molecular dynamics (AMD) calculations. The spin alignment mechanism is shown to be useful for making spin assignments and may have widespread use.

Published
2021
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7. Isotopically resolved neutron total cross sections at intermediate energies

Author

Pruitt, C. D., Charity, R. J., Sobotka, L. G., Elson, J. M., Hoff, D. E. M., Brown, K. W., Atkinson, M. C., Dickhoff, W. H., Lee, H. Y., Devlin, M., Fotiades, N., and Mosby, S.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The neutron total cross sections $\sigma_{tot}$ of $^{16,18}$O, $^{58,64}$Ni, $^{103}$Rh, and $^{112,124}$Sn have been measured at the Los Alamos Neutron Science Center (LANSCE) from low to intermediate energies (3 $\leq E_{lab} \leq$ 450 MeV) by leveraging waveform-digitizer technology. The $\sigma_{tot}$ relative differences between isotopes are presented, revealing additional information about the isovector components needed for an accurate optical-model description away from stability. Digitizer-enabled $\sigma_{tot}$-measurement techniques are discussed and a series of uncertainty-quantified dispersive optical model (DOM) analyses using these new data is presented, validating the use of the DOM for modeling light systems ($^{16,18}$O) and systems with open neutron shells ($^{58,64}$Ni and $^{112,124}$Sn). The valence-nucleon spectroscopic factors extracted for each isotope reaffirm the usefulness of high-energy proton reaction cross sections for characterizing depletion from the mean-field expectation., Comment: 28 pages, 20 figures

Published
2020
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8. Particle decays of levels in $^{11,12}$N and $^{12}$O investigated with the invariant-mass method

Author

Webb, T. B., Charity, R. J., Elson, J. M., Hoff, D. E. M, Pruitt, C. D., Sobotka, L. G., Brown, K. W., Barney, J., Cerizza, G., Estee, J., Jhang, G., Lynch, W. G., Manfredi, J., Morfouace, P., Santamaria, C., Sweany, S., Tsang, M. B., Tsang, T., Wang, S. M., Zhang, Y., Zhu, K., Kuvin, S. A., McNeel, D., Smith, J., Wuosmaa, A. H., and Chajecki, Z.

Subjects
Nuclear Experiment
Abstract

Particle-decaying states of the light nuclei $^{11,12}$N and $^{12}$O were studied using the invariant-mass method. The decay energies and intrinsic widths of a number of states were measured, and the momentum correlations of three-body decaying states were considered. A second 2$p$-decaying 2$^+$ state of $^{12}$O was observed for the first time, and a higher energy $^{12}$O state was observed in the 4$p$+2$\alpha$ decay channel. This 4$p$+2$\alpha$ channel also contains contributions from fission-like decay paths, including $^6$Be$_{g.s.}$+$^{6}$Be$_{g.s.}$. Analogs to these states in $^{12}$O were found in $^{12}$N in the 2$p$+$^{10}$B and 2$p$+$\alpha$+$^6$Li channels. The momentum correlations for the prompt 2$p$ decay of $^{12}$O$_{g.s.}$ were found to be nearly identical to those of $^{16}$Ne$_{g.s.}$, and the correlations for the new 2$^+$ state were found to be consistent with sequential decay through excited states in $^{11}$N. The momentum correlations for the 2$^+_1$ state in $^{12}$O provide a new value for the $^{11}$N ground-state energy. The states in $^{12}$N/$^{12}$O that belong to the $A$=12 isobaric sextet do not deviate from the quadratic isobaric multiplet mass equation (IMME) form., Comment: 16 pages, 16 figures, 7 tables, tables corrected

Published
2019
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9. First observation of unbound $^{11}$O, the mirror of the halo nucleus $^{11}$Li

Author

Webb, T. B., Wang, S. M., Brown, K. W., Charity, R. J., Elson, J. M., Barney, J., Cerizza, G., Chajecki, Z., Estee, J., Hoff, D. E. M., Kuvin, S. A., Lynch, W. G., Manfredi, J., McNeel, D., Morfouace, P., Nazarewicz, W., Pruitt, C. D., Santamaria, C., Smith, J., Sobotka, L. G., Sweany, S., Tsang, C. Y., Tsang, M. B., Wuosmaa, A. H., Zhang, Y., and Zhu, Z.

Subjects
Nuclear Experiment, Nuclear Theory
Abstract

The structure of the extremely proton-rich nucleus $^{11}_{~8}$O$_3$, the mirror of the two-neutron halo nucleus $^{11}_{~3}$Li$_8$, has been studied experimentally for the first time. Following two-neutron knockout reactions with a $^{13}$O beam, the $^{11}$O decay products were detected after two-proton emission and used to construct an invariant-mass spectrum. A broad peak of width $\sim$3\,MeV was observed. Within the Gamow coupled-channel approach, it was concluded that this peak is a multiplet with contributions from the four-lowest $^{11}$O resonant states: $J^{\pi}$=3/2$^-_1$, 3/2$^-_2$, 5/2$^+_1$, and 5/2$^+_2$. The widths and configurations of these states show strong, non-monotonic dependencies on the depth of the $p$-$^9$C potential. This unusual behavior is due to the presence of a broad threshold resonant state in $^{10}$N, which is an analog of the virtual state in $^{10}$Li in the presence of the Coulomb potential. After optimizing the model to the data, only a moderate isospin asymmetry between ground states of $^{11}$O and $^{11}$Li was found., Comment: 6 pages, three figures

Published
2018
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10. Proton Shell Gaps in N=28 Nuclei from the First Complete Spectroscopy Study with FRIB Decay Station Initiator

Author

Cox, I., primary, Xu, Z. Y., additional, Grzywacz, R., additional, Ong, W.-J., additional, Rasco, B. C., additional, Kitamura, N., additional, Hoskins, D., additional, Neupane, S., additional, Ruland, T. J., additional, Allmond, J. M., additional, King, T. T., additional, Lubna, R. S., additional, Rykaczewski, K. P., additional, Schatz, H., additional, Sherrill, B. M., additional, Tarasov, O. B., additional, Ayangeakaa, A. D., additional, Berg, H. C., additional, Bleuel, D. L., additional, Cerizza, G., additional, Christie, J., additional, Chester, A., additional, Davis, J., additional, Dembski, C., additional, Doetsch, A. A., additional, Duarte, J. G., additional, Estrade, A., additional, Fijałkowska, A., additional, Gray, T. J., additional, Good, E. C., additional, Haak, K., additional, Hanai, S., additional, Harke, J. T., additional, Harris, C., additional, Hermansen, K., additional, Hoff, D. E. M., additional, Jain, R., additional, Karny, M., additional, Kolos, K., additional, Laminack, A., additional, Liddick, S. N., additional, Longfellow, B., additional, Lyons, S., additional, Madurga, M., additional, Mogannam, M. J., additional, Nowicki, A., additional, Ogunbeku, T. H., additional, Owens-Fryar, G., additional, Rajabali, M. M., additional, Richard, A. L., additional, Ronning, E. K., additional, Rose, G. E., additional, Siegl, K., additional, Singh, M., additional, Spyrou, A., additional, Sweet, A., additional, Tsantiri, A., additional, Walters, W. B., additional, and Yokoyama, R., additional

Published
2024
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11. Direct Mass Measurements to Inform the Behavior of Sb128m in Nucleosynthetic Environments

Author

Hoff, D. E. M., primary, Kolos, K., additional, Misch, G. W., additional, Ray, D., additional, Liu, B., additional, Valverde, A. A., additional, Brodeur, M., additional, Burdette, D. P., additional, Callahan, N., additional, Clark, J. A., additional, Gallant, A. T., additional, Kondev, F. G., additional, Morgan, G. E., additional, Mumpower, M. R., additional, Orford, R., additional, Porter, W. S., additional, Rivero, F., additional, Savard, G., additional, Scielzo, N. D., additional, Sharma, K. S., additional, Sieja, K., additional, Sprouse, T. M., additional, and Varriano, L., additional

Published
2023
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12. Mirror-symmetry violation in bound nuclear ground states

Author

Hoff, D. E. M., Rogers, A. M., Wang, S. M., Bender, P. C., Brandenburg, K., Childers, K., and Clark, J. A.

Subjects
Conservation laws (Physics) -- Research, Nuclear research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Conservation laws are deeply related to any symmetry present in a physical system.sup.1,2. Analogously to electrons in atoms exhibiting spin symmetries.sup.3, it is possible to consider neutrons and protons in the atomic nucleus as projections of a single fermion with an isobaric spin (isospin) of t = 1/2 (ref. .sup.4). Every nuclear state is thus characterized by a total isobaric spin T and a projection T.sub.z--two quantities that are largely conserved in nuclear reactions and decays.sup.5,6. A mirror symmetry emerges from this isobaric-spin formalism: nuclei with exchanged numbers of neutrons and protons, known as mirror nuclei, should have an identical set of states.sup.7, including their ground state, labelled by their total angular momentum J and parity [pi]. Here we report evidence of mirror-symmetry violation in bound nuclear ground states within the mirror partners strontium-73 and bromine-73. We find that a J.sup. [pi] = 5/2.sup.- spin assignment is needed to explain the proton-emission pattern observed from the T = 3/2 isobaric-analogue state in rubidium-73, which is identical to the ground state of strontium-73. Therefore the ground state of strontium-73 must differ from its J .sup.[pi] = 1/2.sup.- mirror bromine-73. This observation offers insights into charge-symmetry-breaking forces acting in atomic nuclei. Observations of the decay of .sup.73Sr, when compared to its mirror nucleus .sup.73Br, indicate that the spin assignment of their ground states differ, demonstrating mirror-symmetry violation., Author(s): D. E. M. Hoff [sup.1] , A. M. Rogers [sup.1] , S. M. Wang [sup.2] , P. C. Bender [sup.1] , K. Brandenburg [sup.3] , K. Childers [sup.2] [sup.4] [...]

Published
2020
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13. Strong Evidence for N9 and the Limits of Existence of Atomic Nuclei

Author

Charity, R. J., primary, Wylie, J., additional, Wang, S. M., additional, Webb, T. B., additional, Brown, K. W., additional, Cerizza, G., additional, Chajecki, Z., additional, Elson, J. M., additional, Estee, J., additional, Hoff, D. E. M., additional, Kuvin, S. A., additional, Lynch, W. G., additional, Manfredi, J., additional, Michel, N., additional, McNeel, D. G., additional, Morfouace, P., additional, Nazarewicz, W., additional, Pruitt, C. D., additional, Santamaria, C., additional, Sweany, S., additional, Smith, J., additional, Sobotka, L. G., additional, Tsang, M. B., additional, and Wuosmaa, A. H., additional

Published
2023
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14. Production and discovery of neutron-rich isotopes by fragmentation of Pt198

Author

Haak, K., primary, Tarasov, O. B., additional, Chowdhury, P., additional, Rogers, A. M., additional, Sharma, K., additional, Baumann, T., additional, Bazin, D., additional, Bender, P. C., additional, Chen, J., additional, Estrade, A., additional, Famiano, M. A., additional, Foulds-Holt, D. C., additional, Fukuda, N., additional, Gade, A., additional, Ginter, T. N., additional, Gohier, R. W., additional, Hausmann, M., additional, Hill, A. M., additional, Hoff, D. E. M., additional, Klankowski, L., additional, Kwan, E., additional, Li, J., additional, Liddick, S. N., additional, Longfellow, B., additional, Lyons, S., additional, Morse, C., additional, Portillo, M., additional, Rhodes, D., additional, Richard, A. L., additional, Samaranayake, S., additional, Sherrill, B. M., additional, Smith, M. K., additional, Spieker, M., additional, Sumithrarachchi, C. S., additional, Suzuki, H., additional, Wang, K., additional, Waniganeththi, S., additional, Weisshaar, D., additional, and Zhu, S., additional

Published
2023
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15. Experimental study of the S38 excited level scheme

Author

Hoffman, C. R., primary, Lubna, R. S., additional, Rubino, E., additional, Tabor, S. L., additional, Auranen, K., additional, Bender, P. C., additional, Campbell, C. M., additional, Carpenter, M. P., additional, Chen, J., additional, Gott, M., additional, Greene, J. P., additional, Hoff, D. E. M., additional, Huang, T., additional, Iwasaki, H., additional, Kondev, F. G., additional, Lauritsen, T., additional, Longfellow, B., additional, Santamaria, C., additional, Seweryniak, D., additional, Tang, T. L., additional, Wilson, G. L., additional, Wu, J., additional, and Zhu, S., additional

Published
2023
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16. Discovery of the new isotope Lr251 : Impact of the hexacontetrapole deformation on single-proton orbital energies near the Z=100 deformed shell gap

Author

Huang, T., primary, Seweryniak, D., additional, Back, B. B., additional, Bender, P. C., additional, Carpenter, M. P., additional, Chowdhury, P., additional, Clark, R. M., additional, Copp, P. A., additional, He, X.-T., additional, Herzberg, R. D., additional, Hoff, D. E. M., additional, Jayatissa, H., additional, Khoo, T. L., additional, Kondev, F. G., additional, Morgan, G., additional, Morse, C., additional, Korichi, A., additional, Lauritsen, T., additional, Müller-Gatermann, C., additional, Potterveld, D. H., additional, Reviol, W., additional, Rogers, A. M., additional, Saha, S., additional, Savard, G., additional, Sharma, K., additional, Stolze, S., additional, Waniganeththi, S., additional, Wilson, G. L., additional, Wu, J., additional, Xu, Y.-F., additional, and Zhu, S., additional

Published
2022
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17. Establishing the ground-state spin of Kr71

Author

Waniganeththi, S., primary, Hoff, D. E. M., additional, Rogers, A. M., additional, Lister, C. J., additional, Bender, P. C., additional, Brandenburg, K., additional, Childers, K., additional, Clark, J. A., additional, Dombos, A. C., additional, Doucet, E. R., additional, Jin, S., additional, Lewis, R., additional, Liddick, S. N., additional, Meisel, Z., additional, Morse, C., additional, Schatz, H., additional, Schmidt, K., additional, Soltesz, D., additional, and Subedi, S. K., additional

Published
2022
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18. Establishing the ground-state spin of 71Kr

Author

Waniganeththi, S., Hoff, D. E. M., Rogers, A. M., Lister, C. J., Bender, P. C., Brandenburg, K., Childers, K., Clark, J. A., Dombos, A. C., Doucet, E. R., Jin, S., Lewis, R., Liddick, S. N., Meisel, Z., Morse, C., Schatz, H., Schmidt, K., Soltesz, D., and Subedi, S. K.

Abstract

Nuclei in the vicinity of the N=Z line provide many sensitive probes of isospin symmetry. One example concerns the character and sequence of low-lying states of the T=1/2 mirror pair 71Kr and 71Br which has been under debate for several decades. In this paper we report a new measurement of the absolute β-branching to ground and excited states which, taken with our precise lifetime of T1/2=94.9(4)ms, gives a superallowed ground state–to–ground state log(ft) value of 3.64(4). This is only consistent with both 71Br and 71Kr having the same spin and parity, Jπ=5/2−, as expected from mirror symmetry. The β-delayed proton emission to the first-excited state in 70Se was observed for the first time which also strongly supports this assignment.

Published
2022

19. Half-life measurement of the 199-keV isomeric state in Ga76

Author

Chester, A., primary, Brown, B. A., additional, Burcher, S. P., additional, Carpenter, M. P., additional, Carroll, J. J., additional, Chiara, C. J., additional, Copp, P. A., additional, Crider, B. P., additional, Harke, J. T., additional, Hoff, D. E. M., additional, Kolos, K., additional, Liddick, S. N., additional, Longfellow, B., additional, Mogannam, M. J., additional, Ogunbeku, T. H., additional, Prokop, C. J., additional, Rhodes, D., additional, Richard, A. L., additional, Shehu, O. A., additional, Tamashiro, A. S., additional, Unz, R., additional, and Xiao, Y., additional

Published
2022
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20. Identification of a new isomeric state in Zn76 following the β decay of Cu76

Author

Chester, A., primary, Brown, B. A., additional, Burcher, S. P., additional, Carpenter, M. P., additional, Carroll, J. J., additional, Chiara, C. J., additional, Copp, P. A., additional, Crider, B. P., additional, Harke, J. T., additional, Hoff, D. E. M., additional, Kolos, K., additional, Liddick, S. N., additional, Longfellow, B., additional, Mogannam, M. J., additional, Ogunbeku, T. H., additional, Prokop, C. J., additional, Rhodes, D., additional, Richard, A. L., additional, Shehu, O. A., additional, Tamashiro, A. S., additional, Unz, R., additional, and Xiao, Y., additional

Published
2021
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21. Using spin alignment of inelastically excited nuclei in fast beams to assign spins: The spectroscopy of O13 as a test case

Author

Charity, R. J., primary, Webb, T. B., additional, Elson, J. M., additional, Hoff, D. E. M., additional, Pruitt, C. D., additional, Sobotka, L. G., additional, Navrátil, P., additional, Hupin, G., additional, Kravvaris, K., additional, Quaglioni, S., additional, Brown, K. W., additional, Cerizza, G., additional, Estee, J., additional, Lynch, W. G., additional, Manfredi, J., additional, Morfouace, P., additional, Santamaria, C., additional, Sweany, S., additional, Tsang, M. B., additional, Tsang, T., additional, Zhu, K., additional, Kuvin, S. A., additional, McNeel, D., additional, Smith, J., additional, Wuosmaa, A. H., additional, and Chajecki, Z., additional

Published
2021
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22. Level structure of the Tz=-1 nucleus Ar 34 and its relevance for nucleosynthesis in ONe novae

Author

Kennington, A. R. L., Lotay, G., Doherty, D.T., Seweryniak, D., Andreoiu, C., Auranen, K., Carpenter, M. P., Catford, W.N., Deibel, C. M., Hadynska-Klek, K., Hallam, S., Hoff, D. E. M., Huang, T., Janssens, R. V. F., Jazrawi, S., José, J., Kondev, F.G., Lauritsen, T., Li, J., Rogers, A. M., Saiz, J., Savard, G., Stolze, S., Wilson, G. L., Zhu, S., Department of Energy (US), Science and Technology Facilities Council (UK), Natural Sciences and Engineering Research Council of Canada, Ministerio de Economía y Competitividad (España), Generalitat de Catalunya, Ministerio de Ciencia e Innovación (España), and European Commission

Subjects
Nuclear Experiment
Abstract

The Mg24+C12 fusion reaction was used to perform a detailed γ-ray spectroscopy study of the astrophysically important nucleus Ar34. In particular, an experimental setup, coupling the advanced γ-ray tracking array GRETINA with the well-established Argonne fragment mass analyzer (FMA), was employed to obtain excitation energies and spin-parity assignments for excited states in Ar34, both above and below the proton separation energy. For the first time, an angular distribution analysis of in-beam γ rays from fusion-evaporation reactions, using a tracking array, has been performed and Coulomb energy differences of analog states in the T=1, A=34 mirror system, explored from 0 to 6 MeV. Furthermore, we present a comprehensive discussion of the astrophysical Cl33(p,γ) stellar reaction rate, together with implications for the identification of nova presolar grains from sulfur isotopic abundances., This work was supported by the U. S. Department of Energy, Office of Science, Office of Nuclear Physics, under Contract No. DEAC02-06CH11357 and Grants No. DEFG02- 94-ER40834, No. DEFG02-97-ER41041, No. DEFG02- 97-ER41043, No. DEFG02-94-ER40848, and No. DESC0014231. United Kingdom personnel were supported by the Science and Technologies Facilities Council (STFC) and C.A. was supported by the Natural Sciences and Engineering Research Council of Canada. J.J. acknowledges support from Spanish MINECO Grant No. AYA2017-86274-P, the E.U. FEDER funds, and AGAUR/Generalitat de Catalunya Grant No. SGR-661/2017. This research uses resources of ANL’s ATLAS facility, which is a DOE Office of Science User facility

Published
2021
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23. Observation of the Exotic Isotope F13 Located Four Neutrons beyond the Proton Drip Line

Author

Charity, R. J., primary, Webb, T. B., additional, Elson, J. M., additional, Hoff, D. E. M., additional, Pruitt, C. D., additional, Sobotka, L. G., additional, Brown, K. W., additional, Cerizza, G., additional, Estee, J., additional, Lynch, W. G., additional, Manfredi, J., additional, Morfouace, P., additional, Santamaria, C., additional, Sweany, S., additional, Tsang, C. Y., additional, Tsang, M. B., additional, Zhang, Y., additional, Zhu, K., additional, Kuvin, S. A., additional, McNeel, D., additional, Smith, J., additional, Wuosmaa, A. H., additional, and Chajecki, Z., additional

Published
2021
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24. Influence of 73Rb on the ashes of accreting neutron stars

Author

Hoff, D. E. M., Rogers, A. M., Meisel, Z., Bender, P. C., Brandenburg, K., Childers, K., Clark, J. A., Dombos, A. C., Doucet, E. R., Jin, S., Lewis, R., Liddick, S. N., Lister, C. J., Morse, C., Schatz, H., Schmidt, K., Soltesz, D., Subedi, S. K., Wang, S. M., and Waniganeththi, S.

Abstract

We find that the proton separation energy, S(p), of 73Rb is −640(40) keV, deduced from the observation of β-delayed ground-state protons following the decay of 73Sr. This lower-limit determination of the proton separation energy of 73Rb coupled with previous upper limits from nonobservation, provides a full constraint on the mass excess with ΔM(73Rb)=−46.01±0.04 MeV. With this new mass excess and the excitation energy of the Jπ=5/2− isobaric-analog state (T=3/2) in 73Rb, an improved constraint can be put on the mass excess of 73Sr using the isobaric-multiplet mass equation (IMME), and we find ΔM(73Sr)=−31.98±0.37 MeV. These new data were then used to study the composition of ashes on accreting neutron stars following Type I x-ray bursts. Counterintuitively, we find that there should be an enhanced fraction of A>102 nuclei with more negative proton separation energies at the 72Kr rp-process waiting point. Larger impurities of heavier nuclei in the ashes of accreting neutron stars will impact the cooling models for such astrophysical scenarios.

Published
2020

25. Influence of Rb73 on the ashes of accreting neutron stars

Author

Hoff, D. E. M., primary, Rogers, A. M., additional, Meisel, Z., additional, Bender, P. C., additional, Brandenburg, K., additional, Childers, K., additional, Clark, J. A., additional, Dombos, A. C., additional, Doucet, E. R., additional, Jin, S., additional, Lewis, R., additional, Liddick, S. N., additional, Lister, C. J., additional, Morse, C., additional, Schatz, H., additional, Schmidt, K., additional, Soltesz, D., additional, Subedi, S. K., additional, Wang, S. M., additional, and Waniganeththi, S., additional

Published
2020
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27. Erratum: Particle decays of levels in N11,12 and O12 investigated with the invariant-mass method [Phys. Rev. C 100 , 024306 (2019)]

Author

Webb, T. B., primary, Charity, R. J., additional, Elson, J. M., additional, Hoff, D. E. M., additional, Pruitt, C. D., additional, Sobotka, L. G., additional, Brown, K. W., additional, Barney, J., additional, Cerizza, G., additional, Estee, J., additional, Jhang, G., additional, Lynch, W. G., additional, Manfredi, J., additional, Morfouace, P., additional, Santamaria, C., additional, Sweany, S., additional, Tsang, M. B., additional, Tsang, T., additional, Wang, S. M., additional, Zhang, Y., additional, Zhu, K., additional, Kuvin, S. A., additional, McNeel, D., additional, Smith, J., additional, Wuosmaa, A. H., additional, and Chajecki, Z., additional

Published
2020
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28. Search for Nova Presolar Grains: γ -Ray Spectroscopy of Ar34 and its Relevance for the Astrophysical Cl33(p,γ) Reaction

Author

Kennington, A. R. L., primary, Lotay, G., additional, Doherty, D. T., additional, Seweryniak, D., additional, Andreoiu, C., additional, Auranen, K., additional, Carpenter, M. P., additional, Catford, W. N., additional, Deibel, C. M., additional, Hadyńska-Klęk, K., additional, Hallam, S., additional, Hoff, D. E. M., additional, Huang, T., additional, Janssens, R. V. F., additional, Jazrawi, S., additional, José, J., additional, Kondev, F. G., additional, Lauritsen, T., additional, Li, J., additional, Rogers, A. M., additional, Saiz, J., additional, Savard, G., additional, Stolze, S., additional, Wilson, G. L., additional, and Zhu, S., additional

Published
2020
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29. Invariant-mass spectrum of O11

Author

Webb, T. B., primary, Charity, R. J., additional, Elson, J. M., additional, Hoff, D. E. M., additional, Pruitt, C. D., additional, Sobotka, L. G., additional, Brown, K. W., additional, Barney, J., additional, Cerizza, G., additional, Estee, J., additional, Lynch, W. G., additional, Manfredi, J., additional, Morfouace, P., additional, Santamaria, C., additional, Sweany, S., additional, Tsang, M. B., additional, Tsang, T., additional, Zhang, Y., additional, Zhu, K., additional, Kuvin, S. A., additional, McNeel, D., additional, Smith, J., additional, Wuosmaa, A. H., additional, and Chajecki, Z., additional

Published
2020
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30. First Observation of Unbound ^{11}O, the Mirror of the Halo Nucleus ^{11}Li

Author

Webb, T. B., Wang, S. M., Brown, K. W., Charity, R. J., Elson, J. M., Barney, J., Cerizza, G., Chajecki, Z., Estee, J., Hoff, D. E. M., Kuvin, S. A., Lynch, W. G., Manfredi, J., McNeel, D., Morfouace, P., Nazarewicz, W., Pruitt, C. D., Santamaria, C., Smith, J., Sobotka, L. G., Sweany, S., Tsang, C. Y., Tsang, M. B., Wuosmaa, A. H., Zhang, Y., and Zhu, Z.

Subjects
Nuclear Theory (nucl-th), Nuclear Theory, FOS: Physical sciences, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The structure of the extremely proton-rich nucleus $^{11}_{~8}$O$_3$, the mirror of the two-neutron halo nucleus $^{11}_{~3}$Li$_8$, has been studied experimentally for the first time. Following two-neutron knockout reactions with a $^{13}$O beam, the $^{11}$O decay products were detected after two-proton emission and used to construct an invariant-mass spectrum. A broad peak of width $\sim$3\,MeV was observed. Within the Gamow coupled-channel approach, it was concluded that this peak is a multiplet with contributions from the four-lowest $^{11}$O resonant states: $J^{\pi}$=3/2$^-_1$, 3/2$^-_2$, 5/2$^+_1$, and 5/2$^+_2$. The widths and configurations of these states show strong, non-monotonic dependencies on the depth of the $p$-$^9$C potential. This unusual behavior is due to the presence of a broad threshold resonant state in $^{10}$N, which is an analog of the virtual state in $^{10}$Li in the presence of the Coulomb potential. After optimizing the model to the data, only a moderate isospin asymmetry between ground states of $^{11}$O and $^{11}$Li was found., Comment: 6 pages, three figures

Published
2019

31. Particle decays of levels in N11,12 and O12 investigated with the invariant-mass method

Author

Webb, T. B., primary, Charity, R. J., additional, Elson, J. M., additional, Hoff, D. E. M., additional, Pruitt, C. D., additional, Sobotka, L. G., additional, Brown, K. W., additional, Barney, J., additional, Cerizza, G., additional, Estee, J., additional, Jhang, G., additional, Lynch, W. G., additional, Manfredi, J., additional, Morfouace, P., additional, Santamaria, C., additional, Sweany, S., additional, Tsang, M. B., additional, Tsang, T., additional, Wang, S. M., additional, Zhang, Y., additional, Zhu, K., additional, Kuvin, S. A., additional, McNeel, D., additional, Smith, J., additional, Wuosmaa, A. H., additional, and Chajecki, Z., additional

Published
2019
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32. First Observation of Unbound O11 , the Mirror of the Halo Nucleus Li11

Author

Webb, T. B., primary, Wang, S. M., additional, Brown, K. W., additional, Charity, R. J., additional, Elson, J. M., additional, Barney, J., additional, Cerizza, G., additional, Chajecki, Z., additional, Estee, J., additional, Hoff, D. E. M., additional, Kuvin, S. A., additional, Lynch, W. G., additional, Manfredi, J., additional, McNeel, D., additional, Morfouace, P., additional, Nazarewicz, W., additional, Pruitt, C. D., additional, Santamaria, C., additional, Smith, J., additional, Sobotka, L. G., additional, Sweany, S., additional, Tsang, C. Y., additional, Tsang, M. B., additional, Wuosmaa, A. H., additional, Zhang, Y., additional, and Zhu, K., additional

Published
2019
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35. Observation of the Exotic Isotope 13F Located Four Neutrons beyond the Proton Drip Line.

Author

Charity, R. J., Webb, T. B., Elson, J. M., Hoff, D. E. M., Pruitt, C. D., Sobotka, L. G., Brown, K. W., Cerizza, G., Estee, J., Lynch, W. G., Manfredi, J., Morfouace, P., Santamaria, C., Sweany, S., Tsang, C. Y., Tsang, M. B., Zhang, Y., Zhu, K., Kuvin, S. A., and McNeel, D.

Subjects
*PROTON decay, *PROTONS, *WAVE functions, *ISOTOPES, *RESONANCE, *EXOTIC nuclei
Abstract

A 13F resonance was observed following a charge-exchange reaction between a fast 13O beam and a 9Be target. The resonance was found in the invariant-mass distribution of 3p+10C events and probably corresponds to a 5/2+ excited state. The ground state was also expected to be populated, but was not resolved from the background. The observed level decays via initial proton emissions to both the ground and first 2+ state of 12O, which subsequently undergo 2p decay. In addition, there may also be a significant proton decay branch to the second 2+ level in 12O. The wave function associated with the observed level may be collectivized due to coupling to the continuum as is it located just above the threshold for proton decay to the 2+2 state of 12O. [ABSTRACT FROM AUTHOR]

Published
2021
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36. Search for Nova Presolar Grains: γ-Ray Spectroscopy of 34Ar and its Relevance for the Astrophysical 33Cl(p,γ) Reaction.

Author

Kennington, A. R. L., Lotay, G., Doherty, D. T., Seweryniak, D., Andreoiu, C., Auranen, K., Carpenter, M. P., Catford, W. N., Deibel, C. M., Hadyńska-Klęk, K., Hallam, S., Hoff, D. E. M., Huang, T., Janssens, R. V. F., Jazrawi, S., José, J., Kondev, F. G., Lauritsen, T., Li, J., and Rogers, A. M.

Subjects
*NUCLEAR astrophysics, *RESONANT states, *GRAIN, *METEORITES, *NOVAE (Astronomy), *SPECTROMETRY, *NUCLEOSYNTHESIS
Abstract

The discovery of presolar grains in primitive meteorites has initiated a new era of research in the study of stellar nucleosynthesis. However, the accurate classification of presolar grains as being of specific stellar origins is particularly challenging. Recently, it has been suggested that sulfur isotopic abundances may hold the key to definitively identifying presolar grains with being of nova origins and, in this regard, the astrophysical 33Cl(p,γ)34Ar reaction is expected to play a decisive role. As such, we have performed a detailed γ-ray spectroscopy study of 34Ar. Excitation energies have been measured with high precision and spin-parity assignments for resonant states, located above the proton threshold in 34Ar, have been made for the first time. Uncertainties in the 33Cl(p,γ) reaction have been dramatically reduced and the results indicate that a newly identified ℓ=0 resonance at Er=396.9(13) keV dominates the entire rate for T=0.25-0.40 GK. Furthermore, nova hydrodynamic simulations based on the present work indicate an ejected 32S/33S abundance ratio distinctive from type-II supernovae and potentially compatible with recent measurements of a presolar grain. [ABSTRACT FROM AUTHOR]

Published
2020
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37. Direct Mass Measurements to Inform the Behavior of ^{128m}Sb in Nucleosynthetic Environments.

Author

Hoff DEM, Kolos K, Misch GW, Ray D, Liu B, Valverde AA, Brodeur M, Burdette DP, Callahan N, Clark JA, Gallant AT, Kondev FG, Morgan GE, Mumpower MR, Orford R, Porter WS, Rivero F, Savard G, Scielzo ND, Sharma KS, Sieja K, Sprouse TM, and Varriano L

Abstract

Nuclear isomer effects are pivotal in understanding nuclear astrophysics, particularly in the rapid neutron-capture process where the population of metastable isomers can alter the radioactive decay paths of nuclei produced during astrophysical events. The β-decaying isomer ^{128m}Sb was identified as potentially impactful since the β-decay pathway along the A=128 isobar funnels into this state bypassing the ground state. We report the first direct mass measurements of the ^{128}Sb isomer and ground state using the Canadian Penning Trap mass spectrometer at Argonne National Laboratory. We find mass excesses of -84564.8(25)  keV and -84608.8(21)  keV, respectively, resulting in an excitation energy for the isomer of 43.9(33) keV. These results provide the first key nuclear data input for understanding the role of ^{128m}Sb in nucleosynthesis, and we show that it will influence the flow of the rapid neutron-capture process.

Published
2023
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38. Strong Evidence for ^{9}N and the Limits of Existence of Atomic Nuclei.

Author

Charity RJ, Wylie J, Wang SM, Webb TB, Brown KW, Cerizza G, Chajecki Z, Elson JM, Estee J, Hoff DEM, Kuvin SA, Lynch WG, Manfredi J, Michel N, McNeel DG, Morfouace P, Nazarewicz W, Pruitt CD, Santamaria C, Sweany S, Smith J, Sobotka LG, Tsang MB, and Wuosmaa AH

Abstract

The boundaries of the chart of nuclides contain exotic isotopes that possess extreme proton-to-neutron asymmetries. Here we report on strong evidence of ^{9}N, one of the most exotic proton-rich isotopes where more than one half of its constitute nucleons are unbound. With seven protons and two neutrons, this extremely proton-rich system would represent the first-known example of a ground-state five-proton emitter. The invariant-mass spectrum of its decay products can be fit with two peaks whose energies are consistent with the theoretical predictions of an open-quantum-system approach; however, we cannot rule out the possibility that only a single resonancelike peak is present in the spectrum.

Published
2023
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39. Observation of the Exotic Isotope ^{13}F Located Four Neutrons beyond the Proton Drip Line.

Author

Charity RJ, Webb TB, Elson JM, Hoff DEM, Pruitt CD, Sobotka LG, Brown KW, Cerizza G, Estee J, Lynch WG, Manfredi J, Morfouace P, Santamaria C, Sweany S, Tsang CY, Tsang MB, Zhang Y, Zhu K, Kuvin SA, McNeel D, Smith J, Wuosmaa AH, and Chajecki Z

Abstract

A ^{13}F resonance was observed following a charge-exchange reaction between a fast ^{13}O beam and a ^{9}Be target. The resonance was found in the invariant-mass distribution of 3p+^{10}C events and probably corresponds to a 5/2^{+} excited state. The ground state was also expected to be populated, but was not resolved from the background. The observed level decays via initial proton emissions to both the ground and first 2^{+} state of ^{12}O, which subsequently undergo 2p decay. In addition, there may also be a significant proton decay branch to the second 2^{+} level in ^{12}O. The wave function associated with the observed level may be collectivized due to coupling to the continuum as is it located just above the threshold for proton decay to the 2_{2}^{+} state of ^{12}O.

Published
2021
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40. Search for Nova Presolar Grains: γ-Ray Spectroscopy of ^{34}Ar and its Relevance for the Astrophysical ^{33}Cl(p,γ) Reaction.

Author

Kennington ARL, Lotay G, Doherty DT, Seweryniak D, Andreoiu C, Auranen K, Carpenter MP, Catford WN, Deibel CM, Hadyńska-Klęk K, Hallam S, Hoff DEM, Huang T, Janssens RVF, Jazrawi S, José J, Kondev FG, Lauritsen T, Li J, Rogers AM, Saiz J, Savard G, Stolze S, Wilson GL, and Zhu S

Abstract

The discovery of presolar grains in primitive meteorites has initiated a new era of research in the study of stellar nucleosynthesis. However, the accurate classification of presolar grains as being of specific stellar origins is particularly challenging. Recently, it has been suggested that sulfur isotopic abundances may hold the key to definitively identifying presolar grains with being of nova origins and, in this regard, the astrophysical ^{33}Cl(p,γ)^{34}Ar reaction is expected to play a decisive role. As such, we have performed a detailed γ-ray spectroscopy study of ^{34}Ar. Excitation energies have been measured with high precision and spin-parity assignments for resonant states, located above the proton threshold in ^{34}Ar, have been made for the first time. Uncertainties in the ^{33}Cl(p,γ) reaction have been dramatically reduced and the results indicate that a newly identified ℓ=0 resonance at E_{r}=396.9(13)  keV dominates the entire rate for T=0.25-0.40  GK. Furthermore, nova hydrodynamic simulations based on the present work indicate an ejected ^{32}S/^{33}S abundance ratio distinctive from type-II supernovae and potentially compatible with recent measurements of a presolar grain.

Published
2020
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