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13 results on '"D. Muecher"'

1. Enhanced production of 60Fe in massive stars

Author

A. Spyrou, D. Richman, A. Couture, C. E. Fields, S. N. Liddick, K. Childers, B. P. Crider, P. A. DeYoung, A. C. Dombos, P. Gastis, M. Guttormsen, K. Hermansen, A. C. Larsen, R. Lewis, S. Lyons, J. E. Midtbø, S. Mosby, D. Muecher, F. Naqvi, A. Palmisano-Kyle, G. Perdikakis, C. Prokop, H. Schatz, M. K. Smith, C. Sumithrarachchi, and A. Sweet

Subjects
Science
Abstract

Abstract Massive stars are a major source of chemical elements in the cosmos, ejecting freshly produced nuclei through winds and core-collapse supernova explosions into the interstellar medium. Among the material ejected, long-lived radioisotopes, such as 60Fe (iron) and 26Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed 60Fe/26Al ratio by γ-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing 60Fe, and one reaction in particular, the neutron-capture on 59Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of 60Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted 60Fe/26Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models.

Published
2024
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2. Single neutron transfer on 23Ne and its relevance for the pathway of nucleosynthesis in astrophysical X-ray bursts

Author

G. Lotay, J. Henderson, W.N. Catford, F.A. Ali, J. Berean, N. Bernier, S.S. Bhattacharjee, M. Bowry, R. Caballero-Folch, B. Davids, T.E. Drake, A.B. Garnsworthy, F. Ghazi Moradi, S.A. Gillespie, B. Greaves, G. Hackman, S. Hallam, D. Hymers, E. Kasanda, D. Levy, B.K. Luna, A. Mathews, Z. Meisel, M. Moukaddam, D. Muecher, B. Olaizola, N.A. Orr, H.P. Patel, M.M. Rajabali, Y. Saito, J. Smallcombe, M. Spencer, C.E. Svensson, K. Whitmore, and M. Williams

Subjects
Physics, QC1-999
Abstract

We present new experimental measurements of resonance strengths in the astrophysical 23Al(p,γ)24Si reaction, constraining the pathway of nucleosynthesis beyond 22Mg in X-ray burster scenarios. Specifically, we have performed the first measurement of the (d,p) reaction using a radioactive beam of 23Ne to explore levels in 24Ne, the mirror analog of 24Si. Four strong single-particle states were observed and corresponding neutron spectroscopic factors were extracted with a precision of ∼20%. Using these spectroscopic factors, together with mirror state identifications, we have reduced uncertainties in the strength of the key ℓ = 0 resonance at Er = 157 keV, in the astrophysical 23Al(p,γ) reaction, by a factor of 4. Our results show that the 22Mg(p,γ)23Al(p,γ) pathway dominates over the competing 22Mg(α,p) reaction in all but the most energetic X-ray burster events (T>0.85 GK), significantly affecting energy production and the preservation of hydrogen fuel.

Published
2022
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3. Testing microscopically derived descriptions of nuclear collectivity: Coulomb excitation of 22Mg

Author

J. Henderson, G. Hackman, P. Ruotsalainen, S.R. Stroberg, K.D. Launey, J.D. Holt, F.A. Ali, N. Bernier, M.A. Bentley, M. Bowry, R. Caballero-Folch, L.J. Evitts, R. Frederick, A.B. Garnsworthy, P.E. Garrett, B. Jigmeddorj, A.I. Kilic, J. Lassen, J. Measures, D. Muecher, B. Olaizola, E. O'Sullivan, O. Paetkau, J. Park, J. Smallcombe, C.E. Svensson, R. Wadsworth, and C.Y. Wu

Subjects
Physics, QC1-999
Abstract

Many-body nuclear theory utilizing microscopic or chiral potentials has developed to the point that collectivity might be studied within a microscopic or ab initio framework without the use of effective charges; for example with the proper evolution of the E2 operator, or alternatively, through the use of an appropriate and manageable subset of particle–hole excitations. We present a precise determination of E2 strength in 22Mg and its mirror 22Ne by Coulomb excitation, allowing for rigorous comparisons with theory. No-core symplectic shell-model calculations were performed and agree with the new B(E2) values while in-medium similarity-renormalization-group calculations consistently underpredict the absolute strength, with the missing strength found to have both isoscalar and isovector components. The discrepancy between two microscopic models demonstrates the sensitivity of E2 strength to the choice of many-body approximation employed. Keywords: 22Mg, 22Ne, Ab initio, Collectivity, Coulomb excitation

Published
2018
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4. Study of the deformation-driving νd5/2 orbital in 6728Ni39 using one-neutron transfer reactions

Author

J. Diriken, N. Patronis, A.N. Andreyev, S. Antalic, V. Bildstein, A. Blazhev, I.G. Darby, H. De Witte, J. Eberth, J. Elseviers, V.N. Fedosseev, F. Flavigny, Ch. Fransen, G. Georgiev, R. Gernhauser, H. Hess, M. Huyse, J. Jolie, Th. Kröll, R. Krücken, R. Lutter, B.A. Marsh, T. Mertzimekis, D. Muecher, F. Nowacki, R. Orlandi, A. Pakou, R. Raabe, G. Randisi, P. Reiter, T. Roger, M. Seidlitz, M. Seliverstov, K. Sieja, C. Sotty, H. Tornqvist, J. Van De Walle, P. Van Duppen, D. Voulot, N. Warr, F. Wenander, and K. Wimmer

Subjects
Nuclear physics, One-nucleon transfer reactions, RIBs, Nuclear structure, Physics, QC1-999
Abstract

The νg9/2,d5/2,s1/2 orbitals are assumed to be responsible for the swift onset of collectivity observed in the region below 68Ni. Especially the single-particle energies and strengths of these orbitals are of importance. We studied such properties in the nearby 67Ni nucleus, by performing a (d,p)-experiment in inverse kinematics employing a post-accelerated radioactive ion beam (RIB) at the REX-ISOLDE facility. The experiment was performed at an energy of 2.95 MeV/u using a combination of the T-REX particle detectors, the Miniball γ-detection array and a newly-developed delayed-correlation technique as to investigate μs-isomers. Angular distributions of the ground state and multiple excited states in 67Ni were obtained and compared with DWBA cross-section calculations, leading to the identification of positive-parity states with substantial νg9/2 (1007 keV) and νd5/2 (2207 keV and 3277 keV) single-particle strengths up to an excitation energy of 5.8 MeV. 50% of the νd5/2 single-particle strength relative to the νg9/2-orbital is concentrated in and shared between the first two observed 5/2+ levels. A comparison with extended Shell Model calculations and equivalent (3He, d) studies in the region around 9040Zr50 highlights similarities for the strength of the negative-parity pf and positive-parity g9/2 state, but differences are observed for the d5/2 single-particle strength.

Published
2014
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5. Erratum to 'Study of the deformation-driving νd5/2 orbital in 6728Ni39 using one-neutron transfer reactions' [Phys. Lett. B 736 (2014) 533–538]

Author

J. Diriken, N. Patronis, A.N. Andreyev, S. Antalic, V. Bildstein, A. Blazhev, I.G. Darby, H. De Witte, J. Eberth, J. Elseviers, V.N. Fedosseev, F. Flavigny, Ch. Fransen, G. Georgiev, R. Gernhauser, H. Hess, M. Huyse, J. Jolie, Th. Kröll, R. Krücken, R. Lutter, B.A. Marsh, T. Mertzimekis, D. Muecher, F. Nowacki, R. Orlandi, A. Pakou, R. Raabe, G. Randisi, P. Reiter, T. Roger, M. Seidlitz, M. Seliverstov, K. Sieja, C. Sotty, H. Tornqvist, J. Van De Walle, P. Van Duppen, D. Voulot, N. Warr, F. Wenander, and K. Wimmer

Subjects
Physics, QC1-999
Published
2015
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6. Shell evolution approaching the N=20 island of inversion: Structure of Mg29

Author

A. Matta, W. N. Catford, N. A. Orr, J. Henderson, P. Ruotsalainen, G. Hackman, A. B. Garnsworthy, F. Delaunay, R. Wilkinson, G. Lotay, Naofumi Tsunoda, Takaharu Otsuka, A. J. Knapton, G. C. Ball, N. Bernier, C. Burbadge, A. Chester, D. S. Cross, S. Cruz, C. Aa. Diget, T. Domingo, T. E. Drake, L. J. Evitts, F. H. Garcia, S. Hallam, E. MacConnachie, M. Moukaddam, D. Muecher, E. Padilla-Rodal, O. Paetkau, J. Park, J. L. Pore, U. Rizwan, J. Smallcombe, J. K. Smith, K. Starosta, C. E. Svensson, J. Williams, and M. Williams

Subjects
010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, 01 natural sciences
Published
2019

7. Extraction of the Landau-Migdal Parameter from the Gamow-Teller Giant Resonance in Sn132

Author

Hiroshi Tokieda, Hiroyuki Takeda, Masaki Sasano, D. Muecher, M. Shikata, K. Kisamori, D. Kameda, Tomohiro Uesaka, G. Jhang, W. Chao, M. Kurata-Nishimura, M. Kaneko, Jongmin Lee, S. Reichert, H. Sakai, K. Yoneda, Toshiyuki Kubo, W. Powell, R. G. T. Zegers, H. Baba, Yohei Matsuda, Tadaaki Isobe, Nagao Kobayashi, D. Bazin, J. Yasuda, Yosuke Kondo, Toshio Kobayashi, Kentaro Yako, Tomotsugu Wakasa, Noritsugu Nakatsuka, Yasuhiro Togano, T. Motobayashi, Shin'ichiro Michimasa, Juzo Zenihiro, H. Sato, S. Tangwancharoen, Takashi Nakamura, J. Tsubota, A. Krasznahorkay, Susumu Shimoura, C. S. Lee, E. Milman, Motonobu Takaki, L. Stuhl, V. Panin, Toshiyuki Sumikama, N. Fukuda, Shuichi Ota, Yuya Kubota, Yohei Shimizu, T. Murakami, Satoshi Sakaguchi, Hideaki Otsu, T. Tako, M. Sako, Motoki Kobayashi, Shoko Koyama, Naohito Inabe, Masanori Dozono, and H. Suzuki

Subjects
Physics, Pion, 010308 nuclear & particles physics, Giant resonance, 0103 physical sciences, General Physics and Astronomy, Sum rule in quantum mechanics, Atomic physics, 010306 general physics, Nuclear matter, 01 natural sciences, Excitation
Abstract

The key parameter to discuss the possibility of the pion condensation in nuclear matter, i.e., the so-called Landau-Migdal parameter g^{'}, was extracted by measuring the double-differential cross sections for the (p,n) reaction at 216 MeV/u on a neutron-rich doubly magic unstable nucleus, ^{132}Sn with the quality comparable to data taken with stable nuclei. The extracted strengths for Gamow-Teller (GT) transitions from ^{132}Sn leading to ^{132}Sb exhibit the GT giant resonance (GTR) at the excitation energy of 16.3±0.4(stat)±0.4(syst) MeV with the width of Γ=4.7±0.8 MeV. The integrated GT strength up to E_{x}=25 MeV is S_{GT}^{-}=53±5(stat)_{-10}^{+11}(syst), corresponding to 56% of Ikeda's sum rule of 3(N-Z)=96. The present result accurately constrains the Landau-Migdal parameter as g^{'}=0.68±0.07, thanks to the high sensitivity of the GTR energy to g^{'}. In combination with previous studies on the GTR for ^{90}Zr and ^{208}Pb, the result of this work shows the constancy of this parameter in the nuclear chart region with (N-Z)/A=0.11 to 0.24 and A=90 to 208.

Published
2018

8. Study of the deformation-drivingνd5/2orbital in 67 28 Ni 39 using one-neutron transfer reactions

Author

V. Bildstein, B. A. Marsh, T. J. Mertzimekis, Roman Gernhäuser, A. Pakou, J. Jolie, D. Muecher, R. Orlandi, G. Randisi, A. Blazhev, Ch. Fransen, S. Antalic, H. De Witte, J. Elseviers, D. Voulot, C. Sotty, N. Patronis, Herbert Hess, P. Reiter, Kathrin Wimmer, F. Nowacki, R. Krücken, Fredrik Wenander, F. Flavigny, J. Eberth, Kamila Sieja, Riccardo Raabe, Th. Kröll, H. Törnqvist, Georgi P. Georgiev, Iain Darby, N. Warr, Marc Huyse, V. N. Fedosseev, Andrei Andreyev, R. Lutter, M. Seidlitz, Jan Diriken, T. Roger, M. D. Seliverstov, P. Van Duppen, and J. Van de Walle

Subjects
Physics, Nuclear and High Energy Physics, Atomic orbital, Nuclear structure, Neutron, Astrophysics::Earth and Planetary Astrophysics, Deformation (meteorology), Atomic physics
Abstract

The νg9/2, d5/2, s1/2 orbitals are assumed to be responsible for the swift onset of collectivity observed in the region below 68 Ni. Especially the single-particle energies and strengths of these orbitals are of importance. We studied such properties in the nearby

Published
2014

9. Collectivity in the light radon nuclei measured directly via Coulomb excitation

Author

D. Voulot, S. J. Freeman, P. Van Duppen, Liam Gaffney, J. F. Smith, M. Zielinska, Herbert Hess, R. Orlandi, Mark Huyse, Kathrin Wimmer, M. Seidlitz, Michaël Bender, P. Peura, N. Bree, Marcus Scheck, Alick Deacon, D. Muecher, K. Geibel, D. G. Jenkins, A P Robinson, R. Wadsworth, H. De Witte, Janne Pakarinen, A. Blazhev, P. Reiter, V. Kumar, Paul-Henri Heenen, Jan Diriken, Andreas Ekström, Douglas D. DiJulio, K. Singh, Ch. Fransen, Baharak Hadinia, J. Van de Walle, O. Ivanov, Tuomas Grahn, Fredrik Wenander, Th. Kroell, P. A. Butler, S. Martin-Haugh, Panu Rahkila, K. Wrzosek-Lipska, Joonas Konki, B. Bruyneel, U. Jakobsson, N. Kesteloot, Thomas Davinson, N. Warr, A. Petts, Thomas Elias Cocolios, M. Hass, Andrei Andreyev, Department of Chemistry [Cambridge, UK], University of Cambridge [UK] (CAM), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute (ICM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-CHU Pitié-Salpêtrière [AP-HP], Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), CSIR-National Institute of Oceanography, Gravitational-Wave Physics and Astronomy Center (GWPAC), California State University [Fullerton] (CSU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], and Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Population, FOS: Physical sciences, Coulomb excitation, shape coexistence, 01 natural sciences, 0103 physical sciences, Nuclear Physics - Experiment, Neutron, collectivity, Nuclear Experiment (nucl-ex), 010306 general physics, education, Spectroscopy, Nuclear Experiment, Physics, education.field_of_study, ta114, 010308 nuclear & particles physics, Gamma ray, radon, Physique atomique et nucléaire, 3. Good health, Radon, Excited state, Quadrupole, Atomic physics, Ground state
Abstract

Background: Shape coexistence in heavy nuclei poses a strong challenge to state-of-the-art nuclear models, where several competing shape minima are found close to the ground state. A classic region for investigating this phenomenon is in the region around Z=82 and the neutron midshell at N=104. Purpose: Evidence for shape coexistence has been inferred from α-decay measurements, laser spectroscopy, and in-beam measurements. While the latter allow the pattern of excited states and rotational band structures to be mapped out, a detailed understanding of shape coexistence can only come from measurements of electromagnetic matrix elements. Method: Secondary, radioactive ion beams of Rn202 and Rn204 were studied by means of low-energy Coulomb excitation at the REX-ISOLDE in CERN. Results: The electric-quadrupole (E2) matrix element connecting the ground state and first excited 21+ state was extracted for both Rn202 and Rn204, corresponding to B(E2;21+→01+)=29-8+8 and 43-12+17 W.u. respectively. Additionally, E2 matrix elements connecting the 21+ state with the 41+ and 22+ states were determined in Rn202. No excited 0+ states were observed in the current data set, possibly owing to a limited population of second-order processes at the currently available beam energies. Conclusions: The results are discussed in terms of collectivity and the deformation of both nuclei studied is deduced to be weak, as expected from the low-lying level-energy schemes. Comparisons are also made to state-of-the-art beyond-mean-field model calculations and the magnitude of the transitional quadrupole moments are well reproduced., 0, SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2015

10. Experimental study of theNi66(d,p) Ni67one-neutron transfer reaction

Author

C. Sotty, D. Voulot, Th. Kröll, F. Wenander, R. Raabe, D. Muecher, V. Bildstein, V. N. Fedosseev, M. D. Seliverstov, B. A. Marsh, M. Seidlitz, Roman Gernhäuser, P. Reiter, T. Roger, Hans-Jurgen E. Hess, Kathrin Wimmer, A. Pakou, Georgi P. Georgiev, A. Blazhev, J. Van de Walle, F. Flavigny, Jan Diriken, Marc Huyse, A. N. Andreyev, J. Elseviers, N. Patronis, R. Lutter, J. Jolie, G. Randisi, P. Van Duppen, N. Warr, J. Eberth, H. Törnqvist, T. J. Mertzimekis, R. Orlandi, I. G. Darby, Ch. Fransen, S. Antalic, R. Krücken, and H. De Witte

Subjects
Physics, Elastic scattering, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear structure, 01 natural sciences, Atomic orbital, Excited state, 0103 physical sciences, Quadrupole, Neutron, Born approximation, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

The quasi-SU(3) sequence of the positive parity $\ensuremath{\nu}{g}_{9/2},{d}_{5/2},{s}_{1/2}$ orbitals above the $N=40$ shell gap are assumed to induce strong quadrupole collectivity in the neutron-rich Fe $(Z=26)$ and Cr $(Z=24)$ isotopes below the nickel region. In this paper the position and strength of these single-particle orbitals are characterized in the neighborhood of $^{68}\mathrm{Ni} (Z=28,\phantom{\rule{0.16em}{0ex}}N=40)$ through the $^{66}\mathrm{Ni}(d,p)^{67}\mathrm{Ni}$ one-neutron transfer reaction at 2.95 MeV/nucleon in inverse kinematics, performed at the REX-ISOLDE facility in CERN. A combination of the Miniball $\ensuremath{\gamma}$-array and T-REX particle-detection setup was used and a delayed coincidence technique was employed to investigate the 13.3-$\ensuremath{\mu}\mathrm{s}$ isomer at 1007 keV in $^{67}\mathrm{Ni}$. Excited states up to an excitation energy of 5.8 MeV have been populated. Feeding of the $\ensuremath{\nu}{g}_{9/2}$ (1007 keV) and $\ensuremath{\nu}{d}_{5/2}$ (2207 keV and 3277 keV) positive-parity neutron states and negative parity $(\ensuremath{\nu}pf)$ states have been observed at low excitation energy. The extracted relative spectroscopic factors, based on a distorted-wave Born approximation analysis, show that the $\ensuremath{\nu}{d}_{5/2}$ single-particle strength is mostly split over these two excited states. The results are also compared to the distribution of the proton single-particle strength in the $^{90}\mathrm{Zr}$ region $(Z=40,N=50)$.

Published
2015

11. Erratum to 'Study of the deformation-driving νd5/2 orbital in 6728Ni39 using one-neutron transfer reactions' [Phys. Lett. B 736 (2014) 533–538]

Author

A. N. Andreyev, Marc Huyse, A. Blazhev, C. Sotty, Georgi P. Georgiev, P. Reiter, F. Nowacki, J. Jolie, D. Muecher, B. A. Marsh, Kamila Sieja, Jan Diriken, D. Voulot, V. N. Fedosseev, F. Wenander, J. Elseviers, J. Van de Walle, N. Patronis, M. D. Seliverstov, Herbert Hess, F. Flavigny, Kathrin Wimmer, V. Bildstein, G. Randisi, R. Orlandi, I. G. Darby, Ch. Fransen, S. Antalic, Roman Gernhäuser, M. Seidlitz, P. Van Duppen, R. Krücken, Th. Kröll, T. J. Mertzimekis, R. Lutter, J. Eberth, H. Törnqvist, T. Roger, H. De Witte, N. Warr, R. Raabe, and A. Pakou

Subjects
Physics, Nuclear and High Energy Physics, Condensed matter physics, Neutron, Deformation (meteorology), lcsh:Physics, lcsh:QC1-999
Published
2015
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12. Coulomb excitation of $^{31}$Mg

Author

T. Kotthaus, N. Warr, M. Kalkuehler, P. Van Duppen, Vinzenz Bildstein, B. Bruyneel, Reiner Kruecken, O. Ivanov, M. Seidlitz, Heiko Scheit, T. Davinson, J. Jolie, Fredrik Wenander, P. Reiter, Andreas Wiens, Emyr Clement, Herbert Hess, D. Muecher, N. Bree, Andreas Ekström, I. Stefanescu, E. Piselli, R. Lutter, F. Finke, J. Van de Walle, L. M. Fraile, A. Blazhev, K. Geibel, A. Holler, Marc Huyse, Joakim Cederkäll, D. Voulot, Roman Gernhaeuser, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and ISOLDE

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Island of inversion, ISOL, Coulomb excitation, Reduced transition matrix element, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Coincidence, Intruder state, Excited state, Atomic physics, Ground state, Isotopes of magnesium
Abstract

The ground state properties of Mg-31 indicate a change of nuclear shape at N = 19 with a deformed J(pi) = 1/2(+) intruder state as a ground state, implying that Mg-31 is part of the "island of inversion". The collective properties of excited states were the subject of a Coulomb excitation experiment at REX-ISOLDE, CERN, employing a radioactive Mg-31 beam. De-excitation gamma-rays were detected by the MINIBALL gamma-spectrometer in coincidence with scattered particles in a segmented Si-detector. The level scheme of Mg-3I was extended. Spin and parity assignment of the 945 keV state yielded 5/2(+) and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of Mg-30,Mg-31,Mg-32 establishes that for the N = 19 magnesium isotope not only the ground state but also excited states are largely dominated by a deformed pf intruder configuration. (C) 2011 Elsevier B.V. All rights reserved.

Published
2011

13. Enhanced production of 60 Fe in massive stars.

Author

Spyrou A, Richman D, Couture A, Fields CE, Liddick SN, Childers K, Crider BP, DeYoung PA, Dombos AC, Gastis P, Guttormsen M, Hermansen K, Larsen AC, Lewis R, Lyons S, Midtbø JE, Mosby S, Muecher D, Naqvi F, Palmisano-Kyle A, Perdikakis G, Prokop C, Schatz H, Smith MK, Sumithrarachchi C, and Sweet A

Abstract

Massive stars are a major source of chemical elements in the cosmos, ejecting freshly produced nuclei through winds and core-collapse supernova explosions into the interstellar medium. Among the material ejected, long-lived radioisotopes, such as 60 Fe (iron) and 26 Al (aluminum), offer unique signs of active nucleosynthesis in our galaxy. There is a long-standing discrepancy between the observed 60 Fe/ 26 Al ratio by γ-ray telescopes and predictions from supernova models. This discrepancy has been attributed to uncertainties in the nuclear reaction networks producing 60 Fe, and one reaction in particular, the neutron-capture on 59 Fe. Here we present experimental results that provide a strong constraint on this reaction. We use these results to show that the production of 60 Fe in massive stars is higher than previously thought, further increasing the discrepancy between observed and predicted 60 Fe/ 26 Al ratios. The persisting discrepancy can therefore not be attributed to nuclear uncertainties, and points to issues in massive-star models., (© 2024. The Author(s).)

Published
2024
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