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1. The β-decay of 70Kr into 70Br: Restoration of the pseudo-SU(4) symmetry

Author

A. Vitéz-Sveiczer, A. Algora, A.I. Morales, B. Rubio, G.G. Kiss, P. Sarriguren, P. Van Isacker, G. de Angelis, F. Recchia, S. Nishimura, J. Agramunt, V. Guadilla, A. Montaner-Pizá, S.E.A. Orrigo, A. Horváth, D. Napoli, S. Lenzi, A. Boso, V.H. Phong, J. Wu, P.-A. Söderström, T. Sumikama, H. Suzuki, H. Takeda, D.S. Ahn, H. Baba, P. Doornebal, N. Fukuda, N. Inabe, T. Isobe, T. Kubo, S. Kubono, H. Sakurai, Y. Shimizu, C. Sidong, B. Blank, P. Ascher, M. Gerbaux, T. Goigoux, J. Giovinazzo, S. Grévy, T. Kurtukián Nieto, C. Magron, W. Gelletly, Zs. Dombrádi, Y. Fujita, M. Tanaka, P. Aguilera, F. Molina, J. Eberth, F. Diel, D. Lubos, C. Borcea, E. Ganioglu, D. Nishimura, H. Oikawa, Y. Takei, S. Yagi, W. Korten, G. de France, P. Davies, J. Liu, J. Lee, T. Lokotko, I. Kojouharov, N. Kurz, H. Shaffner, and A. Petrovici

Subjects
Beta decay of 70Kr, pn pairing, GT strength distribution, Pseudo-SU(4) symmetry, QRPA calculations, Physics, QC1-999
Abstract

The β-decay of the even-even nucleus 70Kr with Z=N+2, has been investigated at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center using the BigRIPS fragment separator, the ZeroDegree Spectrometer, the WAS3ABI implantation station and the EURICA HPGe cluster array. Fifteen γ-rays associated with the β-decay of 70Kr into 70Br have been identified for the first time, defining ten populated states below Eexc=3300 keV. The half-life of 70Kr was derived with increased precision and found to be t1/2=45.19±0.14 ms. The β-delayed proton emission probability has also been determined as εp=0.545(23)%. An increase in the β-strength to the yrast 1+ state in comparison with the heaviest Z=N+2 system studied so far (62Ge decay) is observed that may indicate increased np correlations in the T=0 channel. The β-decay strength deduced from the results is interpreted in terms of the proton-neutron quasiparticle random-phase approximation (pnQRPA) and also with a schematic model that includes isoscalar and isovector pairing in addition to quadrupole deformation. The application of this last model indicates an approximate realization of pseudo-SU(4) symmetry in this system.

Published
2022
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2. Discovery of 68Br in secondary reactions of radioactive beams

Author

K. Wimmer, P. Doornenbal, W. Korten, P. Aguilera, A. Algora, T. Ando, T. Arici, H. Baba, B. Blank, A. Boso, S. Chen, A. Corsi, P. Davies, G. de Angelis, G. de France, D.T. Doherty, J. Gerl, R. Gernhäuser, D.G. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Niikura, A. Obertelli, D. Lubos, B. Rubio, E. Sahin, T.Y. Saito, H. Sakurai, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, and M. Zielinska

Subjects
Physics, QC1-999
Abstract

The proton-rich isotope 68Br was discovered in secondary fragmentation reactions of fast radioactive beams. Proton-rich secondary beams of 70,71,72Kr and 70Br, produced at the RIKEN Nishina Center and identified by the BigRIPS fragment separator, impinged on a secondary 9Be target. Unambiguous particle identification behind the secondary target was achieved with the ZeroDegree spectrometer. Based on the expected direct production cross sections from neighboring isotopes, the lifetime of the ground or long-lived isomeric state of 68Br was estimated. The results suggest that secondary fragmentation reactions, where relatively few nucleons are removed from the projectile, offer an alternative way to search for new isotopes, as these reactions populate preferentially low-lying states. Keywords: Radioactive beams, New isotope, Direct reaction

Published
2019
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3. Shape coexistence and isospin symmetry in A = 70 nuclei: Spectroscopy of the Tz = −1 nucleus 70Kr

Author

K. Wimmer, W. Korten, T. Arici, P. Doornenbal, P. Aguilera, A. Algora, T. Ando, H. Baba, B. Blank, A. Boso, S. Chen, A. Corsi, P. Davies, G. de Angelis, G. de France, D.T. Doherty, J. Gerl, R. Gernhäuser, D. Jenkins, S. Koyama, T. Motobayashi, S. Nagamine, M. Niikura, A. Obertelli, D. Lubos, B. Rubio, E. Sahin, T.Y. Saito, H. Sakurai, L. Sinclair, D. Steppenbeck, R. Taniuchi, R. Wadsworth, and M. Zielinska

Subjects
Physics, QC1-999
Abstract

Excited states in the Tz=−1 nucleus 70Kr have been populated using inelastic scattering of a radioactive 70Kr beam as well as one- and two-neutron removal reactions from 71,72Kr at intermediate beam energies. The level scheme of 70Kr was constructed from the observed γ-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus 70Se. A second 2+ state and a candidate for the corresponding 42+ state suggest shape coexistence in 70Kr. Keywords: Radioactive beams, Gamma-ray spectroscopy, Mirror symmetry, Shape coexistence

Published
2018
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4. Erratum: Properties of γ -decaying isomers and isomeric ratios in the Sn100 region [Phys. Rev. C 96 , 044311 (2017)]

Author

J. Park, R. Krücken, D. Lubos, R. Gernhäuser, M. Lewitowicz, S. Nishimura, D. S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, I. Čeliković, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, H. Grawe, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, K. Moschner, D. Murai, I. Nishizuka, Z. Patel, M. M. Rajabali, S. Rice, H. Sakurai, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Y. Xu

Subjects
Physics, 010308 nuclear & particles physics, 0103 physical sciences, Atomic physics, 010306 general physics, 01 natural sciences
Published
2021

5. Shape Changes in the Mirror Nuclei Kr70 and Se70

Author

B. Blank, E. Sahin, D. T. Doherty, W. Korten, A. Obertelli, A. Boso, Tomás R. Rodríguez, Hiroyoshi Sakurai, P. Doornenbal, T. Motobayashi, D. G. Jenkins, David Steppenbeck, G. de Angelis, J. Gerl, Roman Gernhäuser, J. Libert, P. Aguilera, J. P. Delaroche, L. Sinclair, Alejandro Algora, P. J. Davies, Michel Girod, T. Saito, D. Lubos, Toshiaki Ando, Ryo Taniuchi, Si-Ge Chen, M. Zielińska, S. Nagamine, H. Baba, R. Wadsworth, Berta Rubio, Shoko Koyama, A. Corsi, Kathrin Wimmer, Megumi Niikura, and T. Arici

Subjects
Physics, Nuclear Theory, Nuclear structure, Stochastic matrix, General Physics and Astronomy, Order (ring theory), Inelastic scattering, 01 natural sciences, Matrix (mathematics), Isospin, 0103 physical sciences, Mirror nuclei, Atomic physics, Anomaly (physics), Nuclear Experiment, 010306 general physics
Abstract

We studied the proton-rich T_{z}=-1 nucleus ^{70}Kr through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0^{+}→2^{+}). Comparison with the other members of the A=70 isospin triplet, ^{70}Br and ^{70}Se, studied in the same experiment, shows a 3σ deviation from the expected linearity of the electromagnetic matrix elements as a function of T_{z}. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei ^{70}Kr and ^{70}Se contrary to the model predictions.

Published
2021

6. β decay of the very neutron-deficient Ge60 and Ge62 nuclei

Author

Momoko Tanaka, E. Ganioǧlu, Gabor Kiss, F. Diel, Daiki Nishimura, G. de Angelis, F. Molina, Naohito Inabe, Toshiyuki Kubo, T. Kurtukian-Nieto, D. R. Napoli, A. Montaner-Pizá, P. A. Söderström, A. Boso, P. Ascher, S. Grévy, A. I. Morales, V. H. Phong, Shunji Nishimura, J. Giovinazzo, P. Aguilera, C. Sidong, Shigeru Kubono, J. Chiba, R. B. Cakirli, Y. Fujita, Hiroyoshi Sakurai, S. Yagi, C. Magron, J. Agramunt, V. Guadilla, B. Rubio, Y. Shimizu, M. Gerbaux, H. Oikawa, D. Lubos, D. S. Ahn, P. Doornenbal, C. Borcea, Shintaro Go, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, S. E.A. Orrigo, N. Fukuda, Jin Wu, Y. Takei, H. Suzuki, Alejandro Algora, T. Goigoux, and W. Gelletly

Subjects
Physics, Isotope, 010308 nuclear & particles physics, Branching fraction, Excited state, 0103 physical sciences, Neutron, Atomic physics, 010306 general physics, Ground state, 7. Clean energy, 01 natural sciences, Fermi Gamma-ray Space Telescope
Abstract

We report here the results of a study of the $\beta$ decay of the proton-rich Ge isotopes, $^{60}$Ge and $^{62}$Ge, produced in an experiment at the RIKEN Nishina Center. We have improved our knowledge of the half-lives of $^{62}$Ge (73.5(1) ms), $^{60}$Ge (25.0(3) ms) and its daughter nucleus, $^{60}$Ga (69.4(2) ms). We measured individual $\beta$-delayed proton and $\gamma$ emissions and their related branching ratios. Decay schemes and absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. A total $\beta$-delayed proton-emission branching ratio of 67(3)% has been obtained for $^{60}$Ge. New information has been obtained on the energy levels populated in $^{60}$Ga and on the 1/2$^-$ excited state in the $\beta p$ daughter $^{59}$Zn. We extracted a ground state to ground state feeding of 85.3(3)% for the decay of $^{62}$Ge. Eight new $\gamma$ lines have been added to the de-excitation of levels populated in the $^{62}$Ga daughter.

Published
2021

7. Spectroscopy of Cd99 and In101 from β decays of In99 and Sn101

Author

F. Browne, Zhengyu Xu, I. Kojouharov, Y. F. Fang, A. Blazhev, Jinguang Wu, D. S. Ahn, Roman Gernhäuser, P. A. Söderström, D. Kameda, B. Blank, Igor T. Čeliković, T. Isobe, Shunji Nishimura, R. Krücken, H. Schaffner, M. Górska, P. Doornenbal, Z. Wang, I. Nishizuka, Toshiyuki Kubo, Stephen Rice, D. Lubos, K. Steiger, S. Ilieva, M. M. Rajabali, Naohito Inabe, Joochun Park, Young-Ki Kim, Younghun Kwon, A. Jungclaus, Hiroshi Suzuki, Hirofumi Watanabe, Y. Shimizu, T. Faestermann, H. Grawe, N. Kurz, P. Boutachkov, Naoki Fukuda, L. Sinclair, Giuseppe Lorusso, H. Baba, N. Goel, Hiroyoshi Sakurai, Toshiyuki Sumikama, K. Moschner, J. Giovinazzo, Hiroyuki Takeda, G. D. Kim, Daichi Murai, M. Lewitowicz, and Zena Patel

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Excited state, 0103 physical sciences, SHELL model, Atomic physics, 010306 general physics, Spectroscopy, Branching (polymer chemistry), 01 natural sciences, Coincidence, Spectral line
Abstract

We report on new γ-ray spectroscopy results from β decays of In99 and Sn101. 30 new γ rays were observed following the β decay of In99, and inconsistencies in the literature with respect to the γ rays following the β decay of Sn101 were addressed with two confirmed cases and two new transitions. The experimental γ-ray energies, intensities, and coincidence relationships are discussed with shell model calculations, where theoretical β-decay branching ratios from the parent nuclei and γ-ray cascades of excited states from the daughter nuclei were combined to generate hypothetical βγ spectra and βγγ coincidence matrices. The most intense β-delayed γ-ray branches in both Cd99 and In101 were well reproduced with this approach, and several γ rays were assigned to new excited states based on their good agreement with shell model predictions.

Published
2020

8. Studying the Exotic Decay $^{70}Kr$ $\rightarrow$ $^{70}Br$

Author

Daiki Nishimura, G. de Angelis, Hiroyoshi Sakurai, Y. Shimizu, P. A. Söderström, Shunji Nishimura, S. Yagi, C. Magron, J. Agramunt, V. Guadilla, JJ Liu, H. Oikawa, S. M. Lenzi, Y. Takei, N. Kurz, W. Gelletly, S. Chen, A. I. Morales, F. Recchia, E. Ganioglu, J. Giovinazzo, H. Baba, Y. Fujita, V. H. Phong, Gabor Kiss, F. Diel, T. Goigoux, H. Suzuki, D. S. Ahn, Zs. Dombradi, T. Kurtukian Nieto, Jin Wu, P. Aguilera, J. Eberth, N. Fukuda, Jenny Lee, B. Rubio, F. Molina, T. Isobe, P. J. Davies, I. Kojouharov, P. Ascher, M. Tanaka, Alejandro Algora, Naohito Inabe, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, S. E.A. Orrigo, P. Doornebal, A. Montaner-Pizá, D. Lubos, C. Borcea, D. R. Napoli, M. Gerbaux, H. Shaffner, S. Grévy, W. Korten, A. Horvath, Toshiyuki Kubo, A. Boso, Shigeru Kubono, A. Vitez-Sveiczer, T. Lokotko, 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), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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), and 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)

Subjects
Nuclear physics, Physics, 010308 nuclear & particles physics, 0103 physical sciences, General Physics and Astronomy, ddc:530, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences
Abstract

Acta physica Polonica / B 51(3), 587 (2020). doi:10.5506/APhysPolB.51.587, Published by Inst. of Physics, Jagellonian Univ., Cracow

Published
2020

9. Shape coexistence revealed in the $N=Z$ isotope $^{72}$Kr through inelastic scattering

Author

Pieter Doornenbal, G. de Angelis, M. Niikura, T. Arici, M. Zielinska, D. Lubos, E. Sahin, D. T. Doherty, Hiroyoshi Sakurai, J. Gerl, Victor Vaquero, D. G. Jenkins, S. Nagamine, Tohru Motobayashi, Shunji Nishimura, V. H. Phong, Suet Nee Chen, Toshiaki Ando, W. Korten, Alexandre Obertelli, R. Gernhäuser, J. Libert, Hidetada Baba, Jin Wu, Shunpei Koyama, P. J. Davies, J.-P. Delaroche, A. Boso, D. Steppenbeck, R. Taniuchi, Kathrin Wimmer, R. Wadsworth, Berta Rubio, Tomás R. Rodríguez, A. Corsi, Michel Girod, G. Kiss, P. Aguilera, T. Goigoux, T. Saito, Alejandro Algora, L. Sinclair, B. Blank, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), RIKEN Nishina Center for Accelerator-Based Science, Science and Technology Facilities Council (UK), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Hungarian Scientific Research Fund, Ministry of Human Capacities (Hungary), 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), and 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)

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Scattering, Yrast, Hadron, FOS: Physical sciences, State (functional analysis), Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Mean field theory, 0103 physical sciences, Nuclear fusion, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Ground state, Nuclear Experiment
Abstract

12 pags., 11 figs., 2 tabs., The N= Z= 36 nucleus Kr has been studied by inelastic scattering at intermediate energies. Two targets, Be and Au, were used to extract the nuclear deformation length, δ, and the reduced E2 transition probability, B(E2). The previously unknown non-yrast 2 and 4 states as well as a new candidate for the octupole 3 state have been observed in the scattering on the Be target and placed in the level scheme based on γ- γ coincidences. The second 2 state was also observed in the scattering on the Au target and the B(E2;22+→01+) value could be determined for the first time. Analyzing the results in terms of a two-band mixing model shows clear evidence for a oblate-prolate shape coexistence and can be explained by a shape change from an oblate ground state to prolate deformed yrast band from the first 2 state. This interpretation is corroborated by beyond mean field calculations using the Gogny D1S interaction., We would like to thank the RIKEN accelerator and BigRIPS teams for providing the high intensity beams. We thank T. Furumoto for providing us with the optical potentials and A. Moro for giving access to an unpublished version of the FRESCO code. This work has been supported by UK STFC under Grant numbers ST/L005727/1 and ST/P003885/1, the Spanish Ministerio de Economía y Competitividad under Grants FPA2011-24553, FPA2014-52823-C2- 1-P, and PGC2018-094583-B-I00, the Program Severo Ochoa (SEV2014-0398), the European Research Council through the ERC Grant No. MINOS-258567, NKFIH (NN128072), and by the ÚNKP-19-4- DE-65 New National Excellence Program of the Ministry of Human Capacities of Hungary. G. K. acknowledges support from the János Bolyai research fellowship of the Hungarian Academy of Sciences. K. W. acknowledges the support from the Spanish Ministerio de Economía y Competitividad RYC-2017-22007.

Published
2020

10. Half-lives of Sr73 and Y76 and the consequences for the proton dripline

Author

F. Browne, V. Werner, T. Isobe, Shin-Ichiro Nishimura, Hirofumi Watanabe, L. Sinclair, P. J. Davies, Toshiyuki Sumikama, Giuseppe Lorusso, D. Lubos, R. Wadsworth, Naoki Fukuda, Jacek Dobaczewski, Zena Patel, Peter Schury, Shigeru Kubono, P. A. Söderström, H. Baba, Hiroyoshi Sakurai, P. Doornenbal, I. Nishizuka, Z. H. Li, Jin Wu, Jack Henderson, Zhengyu Xu, D. G. Jenkins, D. S. Ahn, Alessandro Pastore, Y. F. Fang, Hiroshi Suzuki, A. Estrade, Stephen Rice, Y. Shimizu, and H. Takeda

Subjects
Physics, Proton, 010308 nuclear & particles physics, Proton decay, Nuclear Theory, 7. Clean energy, 01 natural sciences, Beta decay, Nuclear physics, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, medicine, Physics::Accelerator Physics, Density functional theory, Nuclear Experiment, 010306 general physics, Nucleon, Nucleus, Beam (structure)
Abstract

The half-lives of seven nuclei have been determined in the neutron-deficient mass-70 region following their production via fragmentation of a 345 MeV/nucleon Xe124 primary beam on a 740 mg/cm2 Be9 target at the RI Beam Factory, RIKEN. The results include two new (Sr73 and Y76) half-lives and a more precise measurement for the ground-state half-life of Sr74. The new results are discussed with reference to previously published calculations that predict the location of the proton dripline in the light Sr and Y region of the nuclear chart. In addition, differences in the ground-state structure of Rb72 and Y76 are discussed with the aid of density functional theory calculations. These provide a possible explanation for why Rb72 undergoes proton decay while the α-conjugate nucleus Y76 predominantly undergoes β+ decay.

Published
2019

11. Improved Value for the Gamow-Teller Strength of the Sn100 Beta Decay

Author

H. Baba, N. Goel, I. Kojouharov, T. Faestermann, N. Kurz, M. Górska, Young-Ki Kim, Stephen Rice, S. Ilieva, Younghun Kwon, Naoki Fukuda, P. Boutachkov, Shunji Nishimura, Z. Wang, Mustafa Rajabali, B. Blank, A. Blazhev, T. Isobe, K. Moschner, Zhi-Fang Xu, I. Nishizuka, K. Steiger, D. S. Ahn, Igor T. Čeliković, Daichi Murai, Toshiyuki Sumikama, M. Lewitowicz, Joochun Park, J. Giovinazzo, N. Warr, Hiroyuki Takeda, Y. F. Fang, A. Jungclaus, Roman Gernhäuser, Hirofumi Watanabe, Y. Shimizu, Hiroshi Suzuki, D. Kameda, Zena Patel, L. Sinclair, P. Doornenbal, Jinguang Wu, Giuseppe Lorusso, Toshiyuki Kubo, P. A. Söderström, Naohito Inabe, R. Krücken, F. Browne, Hiroyoshi Sakurai, H. Schaffner, and D. Lubos

Subjects
Physics, End point, Proton, 0103 physical sciences, Center (category theory), General Physics and Astronomy, Value (computer science), Atomic physics, 010306 general physics, Spectroscopy, 01 natural sciences, Beta decay, Energy (signal processing)
Abstract

A record number of ^{100}Sn nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the β-decay end point energy of ^{100}Sn were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0^{+}→1^{+} Gamow-Teller decay was improved to B_{GT}=4.4_{-0.7}^{+0.9}. A discrimination between different model calculations was possible for the first time, and the level scheme of ^{100}In is investigated further.

Published
2019

12. New and comprehensive β - and βp -decay spectroscopy results in the vicinity of Sn100

Author

Toshiyuki Sumikama, J. Giovinazzo, Hiroyuki Takeda, Hiroyoshi Sakurai, D. Kameda, Hidetada Baba, T. Faestermann, Stephen Rice, Y. Shimizu, Shunji Nishimura, T. Isobe, I. Kojouharov, S. Ilieva, P. Doornenbal, L. Sinclair, Young-Ki Kim, F. Browne, Y. F. Fang, Giuseppe Lorusso, Younghun Kwon, Hiroshi Watanabe, Igor T. Čeliković, Z. Wang, N. Goel, P. Boutachkov, Jinguang Wu, Joochun Park, K. Steiger, Bertram Blank, D. Lubos, Z. Patel, Naohito Inabe, A. Jungclaus, I. Nishizuka, Zhengyu Xu, Toshiyuki Kubo, Roman Gernhäuser, Mustafa Rajabali, Hiroshi Suzuki, A. Blazhev, P. A. Söderström, D. S. Ahn, G. D. Kim, Daichi Murai, M. Lewitowicz, R. Krücken, H. Schaffner, K. Moschner, H. Grawe, N. Kurz, M. Górska, and Naoki Fukuda

Subjects
Physics, Spins, 010308 nuclear & particles physics, Nuclear structure, 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Neutron, Proton emission, Nuclear Experiment, 010306 general physics, Spectroscopy, Excitation
Abstract

A decay spectroscopy experiment on proton-rich nuclei in the vicinity of the doubly magic Sn100 was carried out at RIKEN Nishina Center. More than 20 nuclei with 43≤Z≤50 and N≤51, produced by fragmentation reactions were investigated via analyses of β-decay, βp-decay, and subsequent γ-ray data. Owing to higher statistics, the precision on the half-lives of many of the ground states and isomers was improved. β-decay endpoint energies of 11 states in 8 nuclei were measured for the first time, and the corresponding QEC and excitation energies were generally consistent with various mass models. Many β-delayed proton emission branching ratios were measured either for the first time or with higher precision compared to literature values, and some of them differed by more than 2σ. Many of the large discrepancies were associated with nuclei with long-lived isomeric states, highlighting large systematic uncertainties involved in these measurements. Twenty-five new γ rays were observed, and ten new states are proposed with unambiguous excitation energies, spins, and parities. Most of the energies of the excited states were consistent within 300 keV or 20%, whichever was greater, compared to shell model predictions in the proton/neutron (p1/2,g9/2) model space assuming a Sr76 core. A signature of a new (1/2-) isomer in Cd97 with T1/2=0.73(7) s was found, in good agreement with shell model predictions.

Published
2019

13. Discovery of $^{68}$Br in secondary reactions of radioactive beams

Author

Ryo Taniuchi, A. Corsi, W. Korten, G. de Angelis, P. J. Davies, A. Obertelli, Kathrin Wimmer, Hiroyoshi Sakurai, T. Motobayashi, R. Wadsworth, Berta Rubio, M. Zielińska, T. Saito, Megumi Niikura, E. Sahin, D. T. Doherty, H. Baba, Shoko Koyama, P. Aguilera, D. Lubos, S. Nagamine, P. Doornenbal, D. G. Jenkins, B. Blank, T. Arici, J. Gerl, A. Boso, Alejandro Algora, David Steppenbeck, Toshiaki Ando, L. Sinclair, Si-Ge Chen, Roman Gernhäuser, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, 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), 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), Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and 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)

Subjects
Nuclear and High Energy Physics, Direct reaction, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Particle identification, Nuclear physics, Direct production, Fragmentation (mass spectrometry), 0103 physical sciences, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Spectrometer, Isotope, 010308 nuclear & particles physics, Projectile, lcsh:QC1-999, Physics::Accelerator Physics, New isotope, Radioactive beams, Nucleon, lcsh:Physics
Abstract

The proton-rich isotope 68Br was discovered in secondary fragmentation reactions of fast radioactive beams. Proton-rich secondary beams of 70,71,72Kr and 70Br, produced at the RIKEN Nishina Center and identified by the BigRIPS fragment separator, impinged on a secondary 9Be target. Unambiguous particle identification behind the secondary target was achieved with the ZeroDegree spectrometer. Based on the expected direct production cross sections from neighboring isotopes, the lifetime of the ground or long-lived isomeric state of 68Br was estimated. The results suggest that secondary fragmentation reactions, where relatively few nucleons are removed from the projectile, offer an alternative way to search for new isotopes, as these reactions populate preferentially low-lying states., Comment: Phys. Lett. B accepted

Published
2019

14. Two-proton Radioactivity: the Interesting Case of \(^{67}\)Kr and Further Studies

Author

N. Fukuda, Y. Fujita, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, P. A. Söderström, Toshiyuki Kubo, P. Ascher, Kathrin Wimmer, D. S. Ahn, S. Grévy, Shunji Nishimura, A. Boso, S. Yagi, R. B. Cakirli, Shintaro Go, W. Gelletly, C. Sidong, Shigeru Kubono, C. Borcea, Jin Wu, A. Algora, C. Magron, H. Suzuki, Gabor Kiss, J. Giovinazzo, H. Oikawa, J. Chiba, P. Doornenbal, Y. Takei, P. Aguilera, V. Guadilla, A. I. Morales, S.E.A. Orrigo, Daiki Nishimura, G. de Angelis, M. Gerbaux, Naohito Inabe, Hiroyoshi Sakurai, B. A. Brown, P. Vi, Y. Shimizu, F. Diel, D. R. Napoli, Berta Rubio, F. Molina, T. Kurtukian-Nieto, D. Lubos, Jorge Agramunt, M. Tanaka, E. Ganioglu, A. Montaner-Piza, T. Goigoux, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), 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), 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Isotope, Proton, 010308 nuclear & particles physics, Nuclear Theory, Theoretical models, General Physics and Astronomy, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, 0103 physical sciences, Physics::Accelerator Physics, Nuclear Experiment, 010306 general physics
Abstract

International audience; We report on the observation of 67Kr that has been produced in an experiment performed at the RIKEN/BigRIPS facility. The two-proton decay of 67Kr has been evidenced and this nucleus is thus the fourth observed long lived ground-state two-proton emitter, after 45Fe, 48Ni and 54Zn. In addition, the decay of several isotopes in the mass region has been investigated. While for previous cases of two-proton radioactivity, the theoretical models could reproduce the measured data, this is not the case anymore for 67Kr. Two interpretations have been proposed to explain this discrepancy: a transition between real two-proton and sequential decay or the influence of deformation. These hypotheses will be tested in future experiments by measuring the angular and energy correlations of the emitted protons.

Published
2020

15. Beta decay of the Tz=-2 nucleus 64Se and its descendants

Author

B. Blank, H. Takeda, Toshiyuki Sumikama, E. Ganioglu, G. G. Kiss, A. Algora, P. Aguilera, DeukSoon Ahn, A. I. Morales, Shin-Ichiro Nishimura, A. Montaner-Pizá, F. Molina, Shigeru Kubono, Daiki Nishimura, G. de Angelis, J. Giovinazzo, F. Diel, R. B. Cakirli, J. Chiba, H. Oikawa, Yoshitaka Fujita, W. Gelletly, V. Guadilla, Jorge Agramunt, Berta Rubio, T. Kurtukian, Momoko Tanaka, C. Sidong, Yoshifumi R. Shimizu, Tomio Kubo, P. A. Söderström, P. Vi, N. Fukuda, Y. Takei, A. Boso, C. Borcea, Shintaro Go, Naohito Inabe, C. Magron, S. E. A. Orrigo, S. Grévy, D. Lubos, H. Suzuki, D. R. Napoli, M. Gerbaux, P. Doornenbal, S. Yang, P. Asher, Jinguang Wu, 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), 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), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and 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)

Subjects
Physics, Paper, History, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Beta decay, Computer Science Applications, Education, ddc, Nuclear physics, Proton radiation, medicine.anatomical_structure, Fragmentation (mass spectrometry), 0103 physical sciences, Bound state, medicine, 010306 general physics, Nucleus
Abstract

International audience; The beta decay of the Tz=-2 nucleus 64Se has been studied in a fragmentation reaction at RIKEN-Nishina Center. 64Se is the heavies Tz=-2 nucleus that decays to bound states in the daughter nucleus and the heaviest case where the mirror reaction 64Zn(3He,t)64Ga on the Tz=+2 64Zn stable target exists and can be compared. Beta-delayed gamma and proton radiation is reported for the 64Se and 64As cases. New levels have been observed in 64As, 64Ge (N=Z), 63Ge and 63Ga. The associated T1/2 values have been obtained.

Published
2018

16. $^{67}$Kr Two-proton Radioactivity: Results and Theoretical Interpretations

Author

P. Ascher, J. Giovinazzo, C. Borcea, Daiki Nishimura, G. de Angelis, A. I. Morales, Y. Fujita, Toshiyuki Kubo, W. Gelletly, Shunji Nishimura, D. S. Ahn, V. Guadilla, Gabor Kiss, P. A. Söderström, A. Boso, S. Yagi, H. Suzuki, D. Lubos, Jorge Agramunt, Hiroyoshi Sakurai, Shigeru Kubono, Shintaro Go, R. B. Cakirli, H. Oikawa, S.E.A. Orrigo, Y. Shimizu, C. Sidong, A. Algora, T. Kurtukian Nieto, C. Magron, S. Grévy, J. Chiba, Kathrin Wimmer, P. Doornenbal, P. Aguilera, B. A. Brown, M. Gerbaux, P. Vi, F. Diel, Jin Wu, T. Goigoux, Y. Takei, D. R. Napoli, Berta Rubio, F. Molina, Naohito Inabe, N. Fukuda, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, M. Tanaka, E. Ganioglu, A. Montaner-Piza, 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), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), 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 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)

Subjects
Physics, Nuclear physics, Proton, Decay energy, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Branching fraction, Nuclear structure, General Physics and Astronomy, Deformation (meteorology), [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy
Abstract

International audience; The two-proton radioactivity is a unique tool to study the nuclear structure beyond the proton drip-line. Since its discovery in 2002, the known emitters have been 19Mg, 45Fe, 48Ni, 54Zn and 67Kr. 67Kr was observed for the first time at the RIKEN Nishina Center in 2015. Its decay energy was measured at 1690(17) keV with a branching ratio of 37(14)%. The half-life, 7.4(30) ms, was found in contradiction with theoretical calculations, pointing out effects of decay dynamics and nuclear deformation.

Published
2018

17. Shape coexistence and isospin symmetry in $A=70$ nuclei: Spectroscopy of the $T_z = -1$ nucleus $^{70}$Kr

Author

Kathrin Wimmer, Ryo Taniuchi, Roman Gernhäuser, P. Aguilera, W. Korten, Toshiaki Ando, T. Saito, Si-Ge Chen, H. Baba, David Steppenbeck, D. G. Jenkins, R. Wadsworth, Berta Rubio, Shoko Koyama, L. Sinclair, Andrea Corsi, E. Sahin, D. T. Doherty, A. Boso, S. Nagamine, J. Gerl, T. Arici, B. Blank, P. Doornenbal, Megumi Niikura, M. Zielińska, Alejandro Algora, P. J. Davies, G. de Angelis, A. Obertelli, D. Lubos, Hiroyoshi Sakurai, T. Motobayashi, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), 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), 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Mirror symmetry, FOS: Physical sciences, Inelastic scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Gamma-ray spectroscopy, Radioactive beams, Shape coexistence, 0103 physical sciences, medicine, ddc:530, Gamma spectroscopy, Nuclear Experiment (nucl-ex), 010306 general physics, Spectroscopy, Nuclear Experiment, Physics, 010308 nuclear & particles physics, Parity (physics), lcsh:QC1-999, medicine.anatomical_structure, Excited state, Isospin, Physics::Accelerator Physics, Atomic physics, Nucleus, lcsh:Physics
Abstract

Excited states in the $T_z=-1$ nucleus $^{70}$Kr have been populated using inelastic scattering of a radioactive $^{70}$Kr beam as well as one- and two-neutron removal reactions from $^{71,72}$Kr at intermediate beam energies. The level scheme of $^{70}$Kr was constructed from the observed $\gamma$-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus $^{70}$Se. A second $2^+$ state and a candidate for the corresponding $4^+_2$ state suggest shape coexistence in $^{70}$Kr., Comment: accepted Phys. Lett. B

Published
2018

18. β decays of the heaviest N=Z−1 nuclei and proton instability of In97

Author

J. Park, R. Krücken, D. Lubos, R. Gernhäuser, M. Lewitowicz, S. Nishimura, D. S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, I. Čeliković, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, H. Grawe, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, K. Moschner, D. Murai, I. Nishizuka, Z. Patel, M. M. Rajabali, S. Rice, H. Sakurai, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Y. Xu

Subjects
Physics, Nuclear physics, Proton, 010308 nuclear & particles physics, 0103 physical sciences, 010306 general physics, Beta (finance), 01 natural sciences, Instability
Published
2018

19. Erratum: Properties of γ -decaying isomers and isomeric ratios in the Sn100 region [Phys. Rev. C 96 , 044311 (2017)]

Author

J. Park, R. Krücken, D. Lubos, R. Gernhäuser, M. Lewitowicz, S. Nishimura, D. S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, I. Čeliković, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, H. Grawe, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, K. Moschner, D. Murai, I. Nishizuka, Z. Patel, M. M. Rajabali, S. Rice, H. Sakurai, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Y. Xu

Subjects
0103 physical sciences, 010306 general physics, 01 natural sciences
Published
2018

20. Discovery of Rb72 : A Nuclear Sandbank Beyond the Proton Drip Line

Author

Y. F. Fang, Jack Henderson, Hiroyoshi Sakurai, F. Browne, Simon M Rice, Jinguang Wu, Zhengyu Xu, V. Werner, H. Takeda, Z. Patel, Z. H. Li, Y. Shimizu, Shigeru Kubono, H. Baba, DeukSoon Ahn, A. Estrade, P-A Soderstrom, Shin-Ichiro Nishimura, P. Doornenbal, D. Lubos, Tomio Kubo, I. Nishizuka, T. Isobe, Peter Schury, Enrico Maglione, P. J. Davies, Lidia S. Ferreira, Hiroshi Suzuki, D. G. Jenkins, Toshiyuki Sumikama, Giuseppe Lorusso, Naoki Fukuda, L. Sinclair, Naohito Inabe, Hirofumi Watanabe, and R. Wadsworth

Subjects
Physics, Proton, 010308 nuclear & particles physics, Proton decay, SHELL model, General Physics and Astronomy, 01 natural sciences, Atomic mass, 0103 physical sciences, Atomic physics, 010306 general physics, Mirror symmetry, Energy (signal processing), Line (formation)
Abstract

In this Letter, the observation of two previously unknown isotopes is presented for the first time: $^{72}\mathrm{Rb}$ with 14 observed events and $^{77}\mathrm{Zr}$ with one observed event. From the nonobservation of the less proton-rich nucleus $^{73}\mathrm{Rb}$, we derive an upper limit for the ground-state half-life of 81 ns, consistent with the previous upper limit of 30 ns. For $^{72}\mathrm{Rb}$, we have measured a half-life of 103(22) ns. This observation of a relatively long-lived odd-odd nucleus, $^{72}\mathrm{Rb}$, with a less exotic odd-even neighbor, $^{73}\mathrm{Rb}$, being unbound shows the diffuseness of the proton drip line and the possibility of sandbanks to exist beyond it. The $^{72}\mathrm{Rb}$ half-life is consistent with a ${5}^{+}\ensuremath{\rightarrow}5/{2}^{\ensuremath{-}}$ proton decay with an energy of 800--900 keV, in agreement with the atomic mass evaluation proton-separation energy as well as results from the finite-range droplet model and shell model calculations using the GXPF1A interaction. However, we cannot explicitly exclude the possibility of a proton transition between ${9}^{+}(^{72}\mathrm{Rb})\ensuremath{\rightarrow}9/{2}^{+}(^{71}\mathrm{Kr})$ isomeric states with a broken mirror symmetry. These results imply that $^{72}\mathrm{Kr}$ is a strong waiting point in x-ray burst $rp$-process scenarios.

Published
2017

21. Publisher's Note: Properties of γ -decaying isomers and isomeric ratios in the Sn100 region [Phys. Rev. C 96 , 044311 (2017)]

Author

J. Park, R. Krücken, D. Lubos, R. Gernhäuser, M. Lewitowicz, S. Nishimura, D. S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, I. Čeliković, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, H. Grawe, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, G. D. Kim, Y.-K. Kim, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, K. Moschner, D. Murai, I. Nishizuka, Z. Patel, M. M. Rajabali, S. Rice, H. Sakurai, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Y. Xu

Subjects
Physics, Crystallography
Abstract

J. Park et al. -- 1 pag. -- Original Article: Properties of γ-decaying isomers and isomeric ratios in the 100 Sn region. Phys. Rev. C 96, 044311 (2017)

Published
2017

22. Properties of γ -decaying isomers and isomeric ratios in the Sn100 region

Author

Joochun Park, A. Jungclaus, Hiroshi Suzuki, G. D. Kim, Daichi Murai, Igor T. Čeliković, M. Lewitowicz, F. Browne, P. A. Söderström, L. Sinclair, Naoki Fukuda, Shunji Nishimura, Y. F. Fang, Toshiyuki Kubo, A. Blazhev, Stephen Rice, R. Krücken, Roman Gernhäuser, S. Ilieva, M. M. Rajabali, M. Górska, Hidetada Baba, Toshiyuki Sumikama, Zena Patel, Zhengyu Xu, T. Isobe, D. S. Ahn, J. Giovinazzo, Hiroyuki Takeda, Young-Ki Kim, T. Faestermann, D. Kameda, H. Grawe, N. Kurz, I. Nishizuka, P. Doornenbal, K. Steiger, Bertram Blank, D. Lubos, Naohito Inabe, Hiroyoshi Sakurai, Hirofumi Watanabe, Y. Shimizu, K. Moschner, Jin Wu, H. Schaffner, P. Boutachkov, Z. Wang, N. Goel, Giuseppe Lorusso, and I. Kojouharov

Subjects
Physics, Internal conversion, Chemical research, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, 0103 physical sciences, Center (category theory), Atomic physics, 010306 general physics, Spectroscopy, 7. Clean energy, 01 natural sciences, Energy (signal processing)
Abstract

Half-lives and energies of $\ensuremath{\gamma}$ rays emitted in the decay of isomeric states of nuclei in the vicinity of the doubly magic $^{100}\mathrm{Sn}$ were measured in a decay spectroscopy experiment at Rikagaku Kenkyusho (The Institute of Physical and Chemical Research) of Japan Nishina Center. The measured half-lives, some with improved precision, are consistent with literature values. Three new results include a 55-keV $E2\phantom{\rule{4pt}{0ex}}\ensuremath{\gamma}$ ray from a new $({4}^{+})$ isomer with ${T}_{1/2}=0.23(6)\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s}$ in $^{92}\mathrm{Rh}$, a 44-keV $E2\phantom{\rule{4pt}{0ex}}\ensuremath{\gamma}$ ray from the $({15}^{+})$ isomer in $^{96}\mathrm{Ag}$, and ${T}_{1/2}({6}^{+})=13(2)$ ns in $^{98}\mathrm{Cd}$. Shell-model calculations of electromagnetic transition strengths in the $({p}_{1/2},{g}_{9/2})$ model space agree with the experimental results. In addition, experimental isomeric ratios were compared to the theoretical predictions derived with an abrasion-ablation model and the sharp cutoff model. The results agreed within a factor of 2 for most isomers. From the nonobservation of time-delayed $\ensuremath{\gamma}$ rays in $^{100}\mathrm{Sn}$, new constraints on the ${T}_{1/2}$, $\ensuremath{\gamma}$-ray energy, and internal conversion coefficients are proposed for the hypothetical isomer in $^{100}\mathrm{Sn}$.

Published
2017

23. Simultaneous investigation of the T=1(Jπ=0+) and T=0(Jπ=9+) β decays in Br70

Author

A. I. Morales, A. Algora, B. Rubio, K. Kaneko, S. Nishimura, P. Aguilera, S. E. A. Orrigo, F. Molina, G. de Angelis, F. Recchia, G. Kiss, V. H. Phong, J. Wu, D. Nishimura, H. Oikawa, T. Goigoux, J. Giovinazzo, P. Ascher, J. Agramunt, D. S. Ahn, H. Baba, B. Blank, C. Borcea, A. Boso, P. Davies, F. Diel, Zs. Dombrádi, P. Doornenbal, J. Eberth, G. de France, Y. Fujita, N. Fukuda, E. Ganioglu, W. Gelletly, M. Gerbaux, S. Grévy, V. Guadilla, N. Inabe, T. Isobe, I. Kojouharov, W. Korten, T. Kubo, S. Kubono, T. Kurtukián Nieto, N. Kurz, J. Lee, S. Lenzi, J. Liu, T. Lokotko, D. Lubos, C. Magron, A. Montaner-Pizá, D. R. Napoli, H. Sakurai, H. Schaffner, Y. Shimizu, C. Sidong, P.-A. Söderström, T. Sumikama, H. Suzuki, H. Takeda, Y. Takei, M. Tanaka, and S. Yagi

Subjects
Physics, Spins, 010308 nuclear & particles physics, Branching fraction, Time decay, Prolate spheroid, 01 natural sciences, Nuclear physics, Excited state, 0103 physical sciences, Pi, Atomic physics, 010306 general physics, Ground state, Excitation
Abstract

The $\beta$ decay of the odd-odd nucleus $^{70}$Br has been investigated with the BigRIPS and EURICA setups at the Radioactive Ion Beam Factory (RIBF) of the RIKEN Nishina Center. The $T=0$ ($J^{\pi}=9^+$) and $T=1$ ($J^{\pi}=0^+$) isomers have both been produced in in-flight fragmentation of $^{78}$Kr with ratios of 41.6(8)\% and 58.4(8)\%, respectively. A half-life of $t_{1/2}=2157^{+53}_{-49}$ ms has been measured for the $J^{\pi}=9^+$ isomer from $\gamma$-ray time decay analysis. Based on this result, we provide a new value of the half-life for the $J^{\pi}=0^+$ ground state of $^{70}$Br, $t_{1/2}=78.42\pm0.51$ ms, which is slightly more precise, and in excellent agreement, with the best measurement reported hitherto in the literature. For this decay, we provide the first estimate of the total branching fraction decaying through the $2^+_1$ state in the daughter nucleus $^{70}$Se, $R(2^+_1)=1.3\pm1.1\%$. We also report four new low-intensity $\gamma$-ray transitions at 661, 1103, 1561, and 1749 keV following the $\beta$ decay of the $J^{\pi}=9^+$ isomer. Based on their coincidence relationships, we tentatively propose two new excited states at 3945 and 4752 keV in $^{70}$Se with most probable spins and parities of $J^{\pi}=(6^+)$ and $(8^+)$, respectively. The observed structure is interpreted with the help of shell-model calculations, which predict a complex interplay between oblate and prolate configurations at low excitation energies.

Published
2017

24. Two-Proton Radioactivity ofKr67

Author

C. Magron, R. B. Cakirli, Daiki Nishimura, G. de Angelis, Toshiyuki Kubo, V. H. Phong, Shunji Nishimura, D. S. Ahn, D. Lubos, P. Ascher, S. Yagi, Hiroyoshi Sakurai, A. Boso, J. Agramunt, V. Guadilla, W. Gelletly, J. Chiba, Y. Shimizu, Shigeru Kubono, B. A. Brown, J. Giovinazzo, F. Diel, H. Oikawa, Y. Fujita, A. Montaner-Pizá, Gabor Kiss, T. Goigoux, C. Borcea, P. Aguilera, Shintaro Go, F. Molina, A. I. Morales, P. A. Söderström, T. Kurtukian Nieto, P. Doornenbal, Momoko Tanaka, Naohito Inabe, M. Gerbaux, S. Grévy, D. R. Napoli, B. Rubio, Kathrin Wimmer, N. Fukuda, B. Blank, Toshiyuki Sumikama, Hiroyuki Takeda, S. E.A. Orrigo, Jin Wu, Y. Takei, E. Ganioglu, H. Suzuki, and Alejandro Algora

Subjects
Physics, Proton, 010308 nuclear & particles physics, Branching fraction, Q value, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, Nuclear physics, Decay energy, 0103 physical sciences, Atomic physics, 010306 general physics, Common emitter, Line (formation)
Abstract

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from 67Kr. At the same time, no evidence for 2p emission of 59Ge and 63Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to 67Kr as being the best new candidate among the three for two-proton radioactivity. 67Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of 67Kr is 7.4(30) ms.

Published
2016

25. Two-Proton Radioactivity of $^{67}$Kr

Author

T, Goigoux, P, Ascher, B, Blank, M, Gerbaux, J, Giovinazzo, S, Grévy, T, Kurtukian Nieto, C, Magron, P, Doornenbal, G G, Kiss, S, Nishimura, P-A, Söderström, V H, Phong, J, Wu, D S, Ahn, N, Fukuda, N, Inabe, T, Kubo, S, Kubono, H, Sakurai, Y, Shimizu, T, Sumikama, H, Suzuki, H, Takeda, J, Agramunt, A, Algora, V, Guadilla, A, Montaner-Piza, A I, Morales, S E A, Orrigo, B, Rubio, Y, Fujita, M, Tanaka, W, Gelletly, P, Aguilera, F, Molina, F, Diel, D, Lubos, G, de Angelis, D, Napoli, C, Borcea, A, Boso, R B, Cakirli, E, Ganioglu, J, Chiba, D, Nishimura, H, Oikawa, Y, Takei, S, Yagi, K, Wimmer, G, de France, S, Go, B A, Brown, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), 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), 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
[PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from ^{67}Kr. At the same time, no evidence for 2p emission of ^{59}Ge and ^{63}Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to ^{67}Kr as being the best new candidate among the three for two-proton radioactivity. ^{67}Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of ^{67}Kr is 7.4(30) ms.

Published
2016

26. Two-proton radioactivity of $^{67}$Kr

Author

T. Goigoux, P. Ascher, B. Blank, M. Gerbaux, J. Giovinazzo, S. Grévy, T. Kurtukian Nieto, C. Magron, J. Agramunt, A. Algora, V. Guadilla, A. Montaner-Piza, A. I. Morales, S. E. A. Orrigo, B. Rubio, D. S. Ahn, P. Doornenbal, N. Fukuda, N. Inabe, G. G. Kiss, T. Kubo, S. Kubono, S. Nishimura, H. Sakurai, Y. Shimizu, C. Sidong, P.-A. Söderström, T. Sumikama, H. Suzuki, H. Takeda, P. Vi, J. Wu, Y. Fujita, M. Tanaka, W. Gelletly, P. Aguilera, F. Molina, F. Diel, D. Lubos, G. de Angelis, D. Napoli, C. Borcea, A. Boso, R. B. Cakirli, E. Ganioglu, J. Chiba, D. Nishimura, H. Oikawa, Y. Takei, S. Yagi, K. Wimmer, G. de France, S. Go, B. A. Brown, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), 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), Yu. E. Penionzhkevich, Yu.G. Sobolev, 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, RIKEN, Proton, 010308 nuclear & particles physics, Radiochemistry, EURICA, Two-proton, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, WAS3ABi, Radioactivity, 0103 physical sciences, 010306 general physics, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2016

27. Status and results from the decay spectroscopy project EURICA (Euroball-RIKEN Cluster Array)

Author

Shin-Ichiro Nishimura, D. Lubos, Giuseppe Lorusso, V. H. Phong, Hiroshi Watanabe, Laura C. Sinclair, T. Isobe, G. Gey, Gary Simpson, I. Kojouharov, Jin Wu, Ayumi Yagi, K. Moschner, G. G. Kiss, P. Doornenbal, Stephen Rice, Toshiyuki Sumikama, Zhengyu Xu, A. Jungclaus, Z. Patel, G. Benzoni, F. Browne, Hiroyoshi Sakurai, H. Baba, N. Kurz, P. A. Söderström, Jan Taprogge, H. Schaffner, Zs. Vajta, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, 0103 physical sciences, Nuclear structure, 010306 general physics, Spectroscopy, 7. Clean energy, 01 natural sciences
Abstract

P.-A. Söderström et al. ; 11 pags., 6 figs. ; Latin American Symposium on Nuclear Physics and Applications, β- and isomer-decay spectroscopy are sensitive probes of nuclear structure, and are often the only techniques capable of providing data for exotic nuclei that are produced with very low rates. Decay properties of exotic nuclei are also essential to model astrophysical events responsible for the evolution of the universe such as the rp- and r-processes. The EURICA project (EUROBALL RIKEN Cluster Array) has been launched in 2012 with the goal of performing spectroscopy of very exotic nuclei. Since 2012, five experimental campaigns have been successfully completed using fragmentation of 124Xe beam and in-flight-fission of 238U beam. In these proceedings we will introduce the experimental setup and highlight some key recent results around 78Ni, 132Sn, and 110Zn published during 2014 and 2015. Published by AIP Publishing.

Published
2016

28. New neutron-deficient isotopes from $^{78}$Kr fragmentation

Author

Shigeru Kubono, Daiki Nishimura, G. de Angelis, Y. Fujita, M. Gerbaux, Hiroyoshi Sakurai, C. Borcea, D. S. Ahn, J. Chiba, Shunji Nishimura, D. Lubos, C. Magron, D. R. Napoli, S. Yagi, H. Suzuki, B. Rubio, J. Agramunt, V. Guadilla, P. A. Söderström, P. Ascher, Toshiyuki Kubo, Naohito Inabe, Jin Wu, Y. Shimizu, H. Oikawa, J. Giovinazzo, Shintaro Go, A. Boso, W. Gelletly, Alejandro Algora, Kathrin Wimmer, F. Diel, Gabor Kiss, F. Molina, R. B. Cakirli, V. H. Phong, T. Kurtukian Nieto, Y. Takei, E. Ganioglu, S. Grévy, N. Fukuda, B. Blank, Toshiyuki Sumikama, P. Doornenbal, Hiroyuki Takeda, S. E.A. Orrigo, T. Goigoux, M. Tanaka, P. Aguilera, A. I. Morales, A. Montaner-Pizá, Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), 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), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, 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), 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), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Isotope, 010308 nuclear & particles physics, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Spectral line, Nuclear physics, Fragmentation (mass spectrometry), 0103 physical sciences, Neutron, Nuclear Experiment (nucl-ex), Atomic physics, 010306 general physics, Nuclear Experiment
Abstract

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the fragmentation of a $^{78}$Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip-line. Clean identification spectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were identified for the first time. In addition, $^{59}$Ge was also observed. Three of these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes $^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic isotopes. These measurements confirm the trend already observed that the empirical parameterization of fragmentation cross sections, EPAX, significantly overestimates experimental cross sections in this mass region., accepted as Rapid Communication in PRC

Published
2016

29. New Isotopes and Proton Emitters–Crossing the Drip Line in the Vicinity ofSn100

Author

I. Čeliković, M. Lewitowicz, R. Gernhäuser, R. Krücken, S. Nishimura, H. Sakurai, D.S. Ahn, H. Baba, B. Blank, A. Blazhev, P. Boutachkov, F. Browne, G. de France, P. Doornenbal, T. Faestermann, Y. Fang, N. Fukuda, J. Giovinazzo, N. Goel, M. Górska, S. Ilieva, N. Inabe, T. Isobe, A. Jungclaus, D. Kameda, Y.-K. Kim, Y. K. Kwon, I. Kojouharov, T. Kubo, N. Kurz, G. Lorusso, D. Lubos, K. Moschner, D. Murai, I. Nishizuka, J. Park, Z. Patel, M. Rajabali, S. Rice, H. Schaffner, Y. Shimizu, L. Sinclair, P.-A. Söderström, K. Steiger, T. Sumikama, H. Suzuki, H. Takeda, Z. Wang, H. Watanabe, J. Wu, and Z. Xu

Subjects
Physics, Range (particle radiation), Isotope, Proton, 010308 nuclear & particles physics, Center (category theory), General Physics and Astronomy, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Production (computer science), Atomic physics, 010306 general physics, Line (formation)
Abstract

Several new isotopes, ^{96}In, ^{94}Cd, ^{92}Ag, and ^{90}Pd, have been identified at the RIKEN Nishina Center. The study of proton drip-line nuclei in the vicinity of ^{100}Sn led to the discovery of new proton emitters ^{93}Ag and ^{89}Rh with half-lives in the submicrosecond range. The systematics of the half-lives of odd-Z nuclei with T_{z}=-1/2 toward ^{99}Sn shows a stabilizing effect of the Z=50 shell closure. Production cross sections for nuclei in the vicinity of ^{100}Sn measured at different energies and target thicknesses were compared to the cross sections calculated by epax taking into account contributions of secondary reactions in the primary target.

Published
2016

30. Beta Decay Spectroscopy of Neutron-Rich Nuclei at RIBF

Author

K. Moschner, Stephen Rice, P. Doornenbal, T. Isobe, R. Daido, Giuseppe Lorusso, Laura C. Sinclair, Hiroshi Watanabe, F. Browne, Hiroki Nishibata, K. Yoshinaga, Ziye Xu, Shin-Ichiro Nishimura, G. Gey, D. Lubos, Toshiyuki Sumikama, Ayumi Yagi, P. A. Söderström, H. Baba, Zs. Vajta, Z. H. Li, Jan Taprogge, Jinguang Wu, Z. Patel, and F. Yifan

Subjects
Nuclear physics, Physics, Neutron, Spectroscopy, Beta decay
Published
2014

31. β-decay spectroscopy at RIBF: The EURICA project

Author

G. Lorusso, S. Nishimura, H. Baba, F. Browne, R. Daido, P. Doornenbal, F. Yifan, G. Gey, T. Isobe, H.-S. Jung, Z. Li, D. Lubos, K. Moschner, H. Nishibata, Z. Patel, S. Rice, L. Sinclair, P.-A. Söderström, T. Sumikama, J. Taprogge, Zs. Vajta, Z. Y. Xu, H. Watanabe, J. Wu, A. Yagi, K. Yoshinaga, and null EURICA Collaboration

Subjects
Nuclear physics, Physics, Gamma spectroscopy, Spectroscopy
Abstract

EURICA is a project at the RIKEN Nishina Center aimed at studying a wide range of exotic nuclei through β-decay measurements and high-resolution γ-ray spectroscopy. During its first two years of operation, about 80 days of beam time have been dedicated to the project allowing the exploration of several very exotic regions of the nuclear chart, which include key nuclei such as 78Ni, 100Sn, 110Zr, 128Pd, and 138Sn. Data analysis of the EURICA experiments is currently ongoing.

Published
2014

32. Proton Dispersion Forces

Author

G. Zundel, K. Kölkenbeck, and W. D. Lubos

Subjects
Quantitative Biology::Biomolecules, Cytosine nucleotide, Proton, Stereochemistry, Polarizability, Chemical physics, Hydrogen bond, Chemistry, Beta sheet, Biophysics, Electrostatics, London dispersion force, Protein secondary structure
Abstract

In the double helix formed by the semiprotonated polycytidylic acid (poly C), both strands are linked via NH+...N hydrogen bonds. It is a known fact that such symmetrical hydrogen bonds with a double minimum potential well are extremely polarizable. This polarizability causes interaction effects, in particular the proton dispersion forces between such hydrogen bonds. These forces result in a shift of the energy levels and a continuum is observed in the infrared (IR) spectra of solutions in which such hydrogen bonds are present. The continuum occurs in the IR spectrum of the semiprotonated poly C, when the former is present in coiled state. If the double helix forms, an extremely broad band of the NH stretching vibration is observed instead of the continuum, since in the double helix all hydrogen bonds are oriented equally to one another and polarize each other mutually to a strong degree. The proton dispersion forces between the hydrogen bonds balance a considerable part of the electrostatic repulsion of the protons and hence enable the double helix to form. It is conceivable that an unsymmetrical double minimum potential well is present in the NH...N bonds in the DNA and RNA. Such bonds may likewise be considerably more polarizable than electron systems and thus, in this case too, proton dispersion forces would contribute to helix stabilization.

Published
1972
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33. Fermi Resonance of Infrared Vibrations in the —NH2 Groups of Polynucleotides

Author

K. Kölkenbeck, W. D. Lubos, and G. Zundel

Subjects
Vibration, Range (particle radiation), Infrared, Chemistry, Group (periodic table), Hydrogen bond, Organic Chemistry, General Chemistry, Fermi resonance, Bending, Atomic physics, Catalysis, Spectral line
Abstract

The —NH2 group causes an intensive band pair in the i.r. spectra of DNA, r.RNA, poly (A + U), and poly (G + C). One band occurs at 3330, another at 3180 cm−1. This band pair is due to the NH stretching vibration of the hydrogen-bonded NH group as well as to the harmonic vibration of the —NH2 bending vibration, whereby these vibrations are coupled via Fermi resonance. This follows on comparison with papers on amines. The weak shoulder in the 3500–3400 cm−1 range is to be assigned to the stretching vibrations of the non hydrogen-bonded NH groups. The doublet structure disappears to a large extent in the denaturated DNA, since the strength of the Fermi resonance depends on the strength of the hydrogen bonds and the hydrogen bonds are of differing strength, due to the bending and stretching. The relative intensities of the two bands are interchanged in the corresponding band pair of the —ND2 groups, for which an explanation can also be given.

Published
1971

34. Shape Changes in the Mirror Nuclei ^{70}Kr and ^{70}Se.

Author

Wimmer K, Korten W, Doornenbal P, Arici T, Aguilera P, Algora A, Ando T, Baba H, Blank B, Boso A, Chen S, Corsi A, Davies P, de Angelis G, de France G, Delaroche JP, Doherty DT, Gerl J, Gernhäuser R, Girod M, Jenkins D, Koyama S, Motobayashi T, Nagamine S, Niikura M, Obertelli A, Libert J, Lubos D, Rodríguez TR, Rubio B, Sahin E, Saito TY, Sakurai H, Sinclair L, Steppenbeck D, Taniuchi R, Wadsworth R, and Zielinska M

Abstract

We studied the proton-rich T_{z}=-1 nucleus ^{70}Kr through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2;0^{+}→2^{+}). Comparison with the other members of the A=70 isospin triplet, ^{70}Br and ^{70}Se, studied in the same experiment, shows a 3σ deviation from the expected linearity of the electromagnetic matrix elements as a function of T_{z}. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei ^{70}Kr and ^{70}Se contrary to the model predictions.

Published
2021
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35. Improved Value for the Gamow-Teller Strength of the ^{100}Sn Beta Decay.

Author

Lubos D, Park J, Faestermann T, Gernhäuser R, Krücken R, Lewitowicz M, Nishimura S, Sakurai H, Ahn DS, Baba H, Blank B, Blazhev A, Boutachkov P, Browne F, Čeliković I, de France G, Doornenbal P, Fang Y, Fukuda N, Giovinazzo J, Goel N, Górska M, Ilieva S, Inabe N, Isobe T, Jungclaus A, Kameda D, Kim YK, Kojouharov I, Kubo T, Kurz N, Kwon YK, Lorusso G, Moschner K, Murai D, Nishizuka I, Patel Z, Rajabali MM, Rice S, Schaffner H, Shimizu Y, Sinclair L, Söderström PA, Steiger K, Sumikama T, Suzuki H, Takeda H, Wang Z, Warr N, Watanabe H, Wu J, and Xu Z

Abstract

A record number of ^{100}Sn nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the β-decay end point energy of ^{100}Sn were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0^{+}→1^{+} Gamow-Teller decay was improved to B_{GT}=4.4_{-0.7}^{+0.9}. A discrimination between different model calculations was possible for the first time, and the level scheme of ^{100}In is investigated further.

Published
2019
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36. Discovery of ^{72}Rb: A Nuclear Sandbank Beyond the Proton Drip Line.

Author

Suzuki H, Sinclair L, Söderström PA, Lorusso G, Davies P, Ferreira LS, Maglione E, Wadsworth R, Wu J, Xu ZY, Nishimura S, Doornenbal P, Ahn DS, Browne F, Fukuda N, Inabe N, Kubo T, Lubos D, Patel Z, Rice S, Shimizu Y, Takeda H, Baba H, Estrade A, Fang Y, Henderson J, Isobe T, Jenkins D, Kubono S, Li Z, Nishizuka I, Sakurai H, Schury P, Sumikama T, Watanabe H, and Werner V

Abstract

In this Letter, the observation of two previously unknown isotopes is presented for the first time: ^{72}Rb with 14 observed events and ^{77}Zr with one observed event. From the nonobservation of the less proton-rich nucleus ^{73}Rb, we derive an upper limit for the ground-state half-life of 81 ns, consistent with the previous upper limit of 30 ns. For ^{72}Rb, we have measured a half-life of 103(22) ns. This observation of a relatively long-lived odd-odd nucleus, ^{72}Rb, with a less exotic odd-even neighbor, ^{73}Rb, being unbound shows the diffuseness of the proton drip line and the possibility of sandbanks to exist beyond it. The ^{72}Rb half-life is consistent with a 5^{+}→5/2^{-} proton decay with an energy of 800-900 keV, in agreement with the atomic mass evaluation proton-separation energy as well as results from the finite-range droplet model and shell model calculations using the GXPF1A interaction. However, we cannot explicitly exclude the possibility of a proton transition between 9^{+}(^{72}Rb)→9/2^{+}(^{71}Kr) isomeric states with a broken mirror symmetry. These results imply that ^{72}Kr is a strong waiting point in x-ray burst rp-process scenarios.

Published
2017
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37. Two-Proton Radioactivity of ^{67}Kr.

Author

Goigoux T, Ascher P, Blank B, Gerbaux M, Giovinazzo J, Grévy S, Kurtukian Nieto T, Magron C, Doornenbal P, Kiss GG, Nishimura S, Söderström PA, Phong VH, Wu J, Ahn DS, Fukuda N, Inabe N, Kubo T, Kubono S, Sakurai H, Shimizu Y, Sumikama T, Suzuki H, Takeda H, Agramunt J, Algora A, Guadilla V, Montaner-Piza A, Morales AI, Orrigo SE, Rubio B, Fujita Y, Tanaka M, Gelletly W, Aguilera P, Molina F, Diel F, Lubos D, de Angelis G, Napoli D, Borcea C, Boso A, Cakirli RB, Ganioglu E, Chiba J, Nishimura D, Oikawa H, Takei Y, Yagi S, Wimmer K, de France G, Go S, and Brown BA

Abstract

In an experiment with the BigRIPS separator at the RIKEN Nishina Center, we observed two-proton (2p) emission from ^{67}Kr. At the same time, no evidence for 2p emission of ^{59}Ge and ^{63}Se, two other potential candidates for this exotic radioactivity, could be observed. This observation is in line with Q value predictions which pointed to ^{67}Kr as being the best new candidate among the three for two-proton radioactivity. ^{67}Kr is only the fourth 2p ground-state emitter to be observed with a half-life of the order of a few milliseconds. The decay energy was determined to be 1690(17) keV, the 2p emission branching ratio is 37(14)%, and the half-life of ^{67}Kr is 7.4(30) ms.

Published
2016
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38. New Isotopes and Proton Emitters-Crossing the Drip Line in the Vicinity of ^{100}Sn.

Author

Čeliković I, Lewitowicz M, Gernhäuser R, Krücken R, Nishimura S, Sakurai H, Ahn DS, Baba H, Blank B, Blazhev A, Boutachkov P, Browne F, de France G, Doornenbal P, Faestermann T, Fang Y, Fukuda N, Giovinazzo J, Goel N, Górska M, Ilieva S, Inabe N, Isobe T, Jungclaus A, Kameda D, Kim YK, Kwon YK, Kojouharov I, Kubo T, Kurz N, Lorusso G, Lubos D, Moschner K, Murai D, Nishizuka I, Park J, Patel Z, Rajabali M, Rice S, Schaffner H, Shimizu Y, Sinclair L, Söderström PA, Steiger K, Sumikama T, Suzuki H, Takeda H, Wang Z, Watanabe H, Wu J, and Xu Z

Abstract

Several new isotopes, ^{96}In, ^{94}Cd, ^{92}Ag, and ^{90}Pd, have been identified at the RIKEN Nishina Center. The study of proton drip-line nuclei in the vicinity of ^{100}Sn led to the discovery of new proton emitters ^{93}Ag and ^{89}Rh with half-lives in the submicrosecond range. The systematics of the half-lives of odd-Z nuclei with T_{z}=-1/2 toward ^{99}Sn shows a stabilizing effect of the Z=50 shell closure. Production cross sections for nuclei in the vicinity of ^{100}Sn measured at different energies and target thicknesses were compared to the cross sections calculated by epax taking into account contributions of secondary reactions in the primary target.

Published
2016
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39. Potential use of procalcitonin as a diagnostic criterion in febrile neutropenia: experience from a multicentre study.

Author

Giamarellou H, Giamarellos-Bourboulis EJ, Repoussis P, Galani L, Anagnostopoulos N, Grecka P, Lubos D, Aoun M, Athanassiou K, Bouza E, Devigili E, Krçmery V, Menichetti F, Panaretou E, Papageorgiou E, and Plachouras D

Subjects
Adult, Aged, Bacterial Infections microbiology, C-Reactive Protein analysis, Calcitonin Gene-Related Peptide, Female, Gram-Negative Bacteria isolation & purification, Gram-Positive Cocci isolation & purification, Humans, Male, Middle Aged, Sensitivity and Specificity, Bacteremia diagnosis, Bacterial Infections diagnosis, Calcitonin blood, Fever of Unknown Origin diagnosis, Neutropenia diagnosis, Protein Precursors blood
Abstract

In order to assess the diagnostic value of procalcitonin, 158 patients with febrile neutropenia from centres across Europe were studied. Patients with fever were diagnosed on the basis of either: (1) clinical, radiological and microbiological criteria; or (2) the procalcitonin value. In the latter case, concentrations of 0.5-1.0 ng/mL were considered diagnostic of localised infection, concentrations of 1.0-5.0 ng/mL of bacteraemia, and concentrations of > 5.0 ng/mL of severe sepsis. Procalcitonin and C-reactive protein were estimated daily in serum by immunochemiluminescence and nephelometry, respectively. Overall, the sensitivity (specificity) of procalcitonin for bacteraemia was 44.2% (64.3%) at concentrations of 1.0-5.0 ng/mL, and 83.3% (100%) for severe sepsis at concentrations of > 5.0 ng/mL. It was concluded that procalcitonin is a marker strongly suggestive of severe sepsis at concentrations of > 5.0 ng/mL. Estimated concentrations of < 0.5 ng/mL indicate that infection is unlikely, but it was observed that bacteraemia associated with coagulase-negative staphylococci may fail to elevate serum procalcitonin levels.

Published
2004
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