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Author |
Wimmer, K. et al; Algora, A.; Rubio, B. |
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Title |
Shape coexistence revealed in the N = Z isotope Kr-72 through inelastic scattering |
Type |
Journal Article |
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Year |
2020 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
56 |
Issue |
6 |
Pages |
159 - 12pp |
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Keywords |
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Abstract |
The N = Z = 36 nucleus Kr-72 has been studied by inelastic scattering at intermediate energies. Two targets, Be-9 and Au-197, were used to extract the nuclear deformation length, delta(N), 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 gamma – gamma coincidences. The second 2(+) state was also observed in the scattering on the Au target and the B(E2; 2(2)(+) -> 0(1)(+)) 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. |
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Address  |
[Wimmer, K.; Ando, T.; Koyama, S.; Nagamine, S.; Niikura, M.; Saito, T. Y.; Sakurai, H.; Taniuchi, R.] Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan, Email: k.wimmer@csic.es |
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Publisher |
Springer |
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Language |
English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
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Conference |
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Notes |
WOS:000540063900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4428 |
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Author |
Wimmer, K. et al; Algora, A.; Rubio, B. |
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Title |
Shape coexistence and isospin symmetry in A=70 nuclei: Spectroscopy of the T-z =-1 nucleus Kr-70 |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
785 |
Issue |
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Pages |
441-446 |
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Keywords |
Radioactive beams; Gamma-ray spectroscopy; Mirror symmetry; Shape coexistence |
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Abstract |
Excited states in the T-z = -1 nucleus Kr-70 have been populated using inelastic scattering of a radioactive Kr-70 beam as well as one- and two-neutron removal reactions from Kr-71,Kr-72 at intermediate beam energies. The level scheme of Kr-70 was constructed from the observed gamma-ray transitions and coincidences. Tentative spin and parity assignments were made based on comparison with the mirror nucleus Se-70. Asecond 2(+) state and a candidate for the corresponding 4(2)(+) state suggest shape coexistence in Kr-70. |
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Address |
[Wimmer, K.; Ando, T.; Koyama, S.; Nagamine, S.; Niikura, M.; Saito, T. Y.; Sakurai, H.; Taniuchi, R.] Univ Tokyo, Dept Phys, Bunkyo Ku, 7-3-1 Hongo, Tokyo 1130033, Japan, Email: wimmer@phys.s.u-tokyo.ac.jp |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000447424000064 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3795 |
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Author |
Wilson, J.N. et al; Algora, A. |
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Title |
Angular momentum generation in nuclear fission |
Type |
Journal Article |
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Year |
2021 |
Publication |
Nature |
Abbreviated Journal |
Nature |
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Volume |
590 |
Issue |
7847 |
Pages |
566-570 |
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Keywords |
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Abstract |
When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning(1); this phenomenon has been a mystery in nuclear physics for over 40 years(2,3). The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum(4-12). Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the gamma-ray heating problem in nuclear reactors(13,14), for the study of the structure of neutron-rich isotopes(15,16), and for the synthesis and stability of super-heavy elements(17,18). gamma-ray spectroscopy experiments on the origin of spin in the products of nuclear fission of spin-zero nuclei suggest that the fission fragments acquire their spin after scission, rather than before. |
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Address |
[Wilson, J. N.; Thisse, D.; Lebois, M.; Jovancevic, N.; Adsley, P.; Babo, M.; Chakma, R.; Delafosse, C.; Haefner, G.; Hauschild, K.; Ibrahim, F.; Ljungvall, J.; Lopez-Martens, A.; Lozeva, R.; Matea, I; Nemer, J.; Popovitch, Y.; Qi, L.; Tocabens, G.; Verney, D.] Univ Paris Saclay, IJC Lab, CNRS, IN2P3, Orsay, France, Email: jonathan.wilson@ijclab.in2p3.fr |
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Publisher |
Nature Research |
Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0028-0836 |
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Notes |
WOS:000621583600006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4717 |
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Author |
Wilkinson, C.; Garcia Soto, A. |
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Title |
Low-ν method with LHC neutrinos |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
109 |
Issue |
3 |
Pages |
033010 - 19pp |
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Keywords |
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Abstract |
The Forward Physics Facility (FPF) plans to use neutrinos produced at the Large Hadron Collider to make a variety of measurements at previously unexplored TeV energies. Its primary goals include precision measurements of the neutrino cross section and using the measured neutrino flux both to uncover information about far-forward hadron production and to search for various beyond standard model scenarios. However, these goals have the potential to conflict: Extracting information about the flux or cross section relies upon an assumption about the other. In this paper, we demonstrate that the FPF can use the low-nu method-a technique for constraining the flux shape by isolating neutrino interactions with low energy transfer to the nucleus-to break this degeneracy. We show that the low-nu method is effective for extracting the nu μflux shape, in a model-independent way. We discuss its application for extracting the nu over bar μflux shape but find that this is significantly more model dependent. Finally, we explore the precision to which the nu μflux shape could be constrained at the FPF for a variety of proposed detector options. We find that the precision would be sufficient to discriminate between various realistic flux models. |
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Address |
[Wilkinson, C.] Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA, Email: cwilkinson@lbl.gov; |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:001183228500009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5986 |
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Author |
CALICE Collaboration (White, A. et al); Irles, A. |
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Title |
Design, construction and commissioning of a technological prototype of a highly granular SiPM-on-tile scintillator-steel hadronic calorimeter |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of Instrumentation |
Abbreviated Journal |
J. Instrum. |
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Volume |
18 |
Issue |
11 |
Pages |
P11018 - 39pp |
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Keywords |
Calorimeters; Detector alignment and calibration methods (lasers, sources, par ticle- beams); Detector design and construction technologies and materials |
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Abstract |
The CALICE collaboration is developing highly granular electromagnetic and hadronic calorimeters for detectors at future energy frontier electron-positron colliders. After successful tests of a physics prototype, a technological prototype of the Analog Hadron Calorimeter has been built, based on a design and construction techniques scalable to a collider detector. The prototype consists of a steel absorber structure and active layers of small scintillator tiles that are individually read out by directly coupled SiPMs. Each layer has an active area of 72 x 72 cm2 and a tile size of 3 x 3 cm2. With 38 active layers, the prototype has nearly 22, 000 readout channels, and its total thickness amounts to 4.4 nuclear interaction lengths. The dedicated readout electronics provide time stamping of each hit with an expected resolution of about 1 ns. The prototype was constructed in 2017 and commissioned in beam tests at DESY. It recorded muons, hadron showers and electron showers at different energies in test beams at CERN in 2018. In this paper, the design of the prototype, its construction and commissioning are described. The methods used to calibrate the detector are detailed, and the performance achieved in terms of uniformity and stability is presented. |
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Address |
[White, A.; Yu, J.] Univ Texas Arlington, Dept Phys, Arlington, TX 76019 USA |
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Corporate Author |
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Thesis |
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Publisher |
IOP Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1748-0221 |
ISBN |
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Medium |
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Area |
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Conference |
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Notes |
WOS:001127235400003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5874 |
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