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Author Caballero-Folch, R. et al; Agramunt, J.; Tain, J.L.; Algora, A.; Domingo-Pardo, C.; Guadilla, V.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A.
Title First determination of beta-delayed multiple neutron emission beyond A=100 through direct neutron measurement: The P-2n value of Sb-136 Type Journal Article
Year 2018 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 98 Issue 3 Pages 034310 - 10pp
Keywords
Abstract Background: beta-delayed multiple neutron emission has been observed for some nuclei with A <= 100 being the Rb-100 the heaviest beta 2n emitter measured to date. So far only 25 P-2n values have been determined for the approximate to 300 nuclei that may decay in this way. Accordingly it is of interest to measure P-2n values for the other possible multiple neutron emitters throughout the chart of the nuclides. It is of particular interest to make such a measurement for nuclei with A > 100 to test the predictions of theoretical models and simulation tools for the decays of heavy nuclei in the region of very neutron-rich nuclei. In addition the decay properties of these nuclei are fundamental for the understanding of astrophysical nucleosynthesis processes such as the r-process and safety inputs for nuclear reactors. Purpose: To determine for the first time the two-neutron branching ratio the P-2n value for Sb-136 through a direct neutron measurement and to provide precise P-1n values for Sb-136 and Te-136. Method: A pure beam of each isotope of interest was provided by the JYFLTRAP Penning trap at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyvaskyla Finland. The purified ions were implanted into a moving tape at the end of the beam line. The detection setup consisted of a plastic scintillator placed right behind the implantation point after the tape to register the beta decays and the BELEN detector based on neutron counters embedded in a polyethylene matrix. The analysis was based on the study of the beta- and neutron-growth-and-decay curves and the beta-one-neutron and beta-two-neutron time correlations which allowed us the determination of the neutron branching ratios. Results: The P-2n value of Sb-136 was found to be 0.14(3)% and the measured P-1n values for Sb-136 and Te-136 were found to be 32.2(15)% and 1.47(6)% respectively. Conclusions: The measured P-2n value is a factor 44 smaller than predicted by the finite-range droplet model plus the quasiparticle random-phase approximation (FRDM+QRPA) model used for r-process calculations.
Address [Caballero-Folch, R.; Dillmann, I] TRIUMF, Vancouver, BC V6T 2A3, Canada, Email: rcaballero-folch@triumf.ca
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000444207600003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3728
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Author Phong, V.H. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A.
Title Observation of a μs isomer in In-134(49)85: Proton-neutron coupling “southeast” of Sn-132(50)82 Type Journal Article
Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 100 Issue 1 Pages 011302 - 6pp
Keywords
Abstract We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus In-134. The nuclei of interest were produced by in-flight fission of a U-238 beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a gamma ray of energy 56.7(1) keV and with a half-life of T-1/2 = 3.5(4) μs. Based on the comparison with shell-model calculations, we interpret the isomer as the I-pi = 5(-) member of the pi 0g(9/2)(-1) circle times nu 1f(7/2)(3) multiplet, decaying to the I-pi = 7(-) ground state with a reduced-transition probability of B(E2; 5(-) -> 7(-)) = 0.53(6) W.u. Observation of this isomer, and lack of evidence in the current work for a I-pi = 5(-) isomer decay in In-132, provides a benchmark of the proton-neutron interaction in the region of the nuclear chart “southeast” of Sn-132, where experimental information on excited states is sparse.
Address [Phong, V. H.; Lorusso, G.; Liu, J.; Matsui, K.; Nishimura, S.; Ahn, D. S.; Baba, H.; Go, S.; Isobe, T.; Kiss, G.; Kubono, S.; Sakurai, H.; Shimizu, Y.; Sumikama, T.; Suzuki, H.; Takeda, H.] RIKEN, RIKEN Nishina Ctr, 2-1 Hirosawa, Wako, Saitama 3510198, Japan, Email: giuseppe.lorusso@npl.co.uk
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000477895400001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4080
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Author Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A.
Title Strong one-neutron emission from two-neutron unbound states in beta decays of the r-process nuclei Ga-86,Ga-87 Type Journal Article
Year 2019 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 100 Issue 3 Pages 031302 - 6pp
Keywords
Abstract beta-delayed one-neutron and two-neutron branching ratios (P-1n and P-2n) have been measured in the decay of A = 84 to 87 Ga isotopes at the Radioactive-Isotope Beam Factory (RIBF) at the RIKEN Nishina Center using a high-efficiency array of He-3 neutron counters (BRIKEN). Two-neutron emission was observed in the decay of Ga-84,Ga-85,Ga-87 for the first time and the branching ratios were measured to be P-2n = 1.6(2)%, 1.3(2)%, and 10.2(28)(stat)(5)(sys)%, respectively. One-neutron branching ratio of Ga-87 (P-1n = 81(9)(stat)(8)(sys)%) and half-life of 29(4) ms were measured for the first time. The branching ratios of Ga-86 were also measured to be P-1n = 74(2)(stat)(8)(sys)% and 16.2(9)(stat)(6)(sys)% with better precision than a previous study. The observation that P-1n > P-2n for both Ga-86,Ga-87 was unexpected and is interpreted as a signature of dominating one-neutron emission from the two-neutron unbound excited states in Ge-86,Ge-87. In order to interpret the experimental results, shell-model and Hauser-Feshbach statistical model calculations of delayed particle and gamma-ray emission probabilities were performed. This model framework reproduces the experimental results. The shell model alone predicts P-2n significantly larger than P-1n for the Ga-87 decay, and it is necessary to invoke a statistical description to successfully explain the observation that P-1n > P-2n. Our new results demonstrate the relevance and importance of a statistical description of neutron emission for the prediction of the decay properties of multineutron emitters and that it must be included in the r-process modeling.
Address [Yokoyama, R.; Grzywacz, R.; Rasco, B. C.; Brewer, N.; Heideman, J.; King, T. T.; Madurga, M.; Singh, M.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA, Email: ryokoyam@utk.edu
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000486641000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4145
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Author Wu, J. et al; Algora, A.; Agramunt, J.; Morales, A.I.; Orrigo, S.E.A.; Tain, J.L.; Tarifeño-Saldivia, A.; Tolosa-Delgado, A.
Title First observation of isomeric states in 111Zr, 113Nb, and 115Mo Type Journal Article
Year 2022 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 106 Issue 6 Pages 064328 - 5pp
Keywords
Abstract Isomeric states in the neutron-rich nuclei 111Zr [T1/2 = 0.10(7) μs], 113Nb [T1/2 = 0.7(4) μs], 115Mo [T1/2 = 46(3) μs] were first identified at the Radioactive Ion Beam Factory (RIBF) of RIKEN by using in-flight fission and fragmentation of a 238U beam at an energy of 345 MeV/u. This is a brief report of the gamma transitions de -exciting from isomeric states and half-lives measurements, which provides the first spectroscopy in the nuclear region of prolate-to-oblate shape-phase transition around mass A approximate to 110.
Address [Wu, J.] Brookhaven Natl Lab, Natl Nucl Data Ctr, Upton, NY 11973 USA, Email: jwu2@bnl.gov
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:000906391600002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5452
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Author Yokoyama, R. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tolosa-Delgado, A.
Title β-delayed neutron emissions from N > 50 gallium isotopes Type Journal Article
Year 2023 Publication Physical Review C Abbreviated Journal Phys. Rev. C
Volume 108 Issue 6 Pages 064307 - 15pp
Keywords
Abstract beta-delayed gamma-neutron spectroscopy has been performed on the decay of A=84 to 87 gallium isotopes at the RI-beam Factory at the RIKEN Nishina Center using a high-efficiency array of 3He neutron counters (BRIKEN). beta-2n-gamma events were measured in the decays of all of the four isotopes for the first time, which is direct evidence for populating the excited states of two-neutron daughter nuclei. Detailed decay schemes with the gamma branching ratios were obtained for these isotopes, and the neutron emission probabilities (P-xn) were updated from the previous study. Hauser-Feshbach statistical model calculations were performed to understand the experimental branching ratios. We found that the P-1n and P-2n values are sensitive to the nuclear level densities of 1n daughter nuclei and showed that the statistical model reproduced the P-2n/P-1n ratio better when experimental levels plus shell-model level densities fit by the Gilbert-Cameron formula were used as the level-density input. We also showed the neutron and gamma branching ratios are sensitive to the ground-state spin of the parent nucleus. Our statistical model analysis suggested J <= 3 for the unknown ground-state spin of the odd-odd nucleus Ga-86, from the I gamma(4(+)-> 2(+))/I-gamma(2(+)-> 0(+)) ratio of Ga-84 and the P-2n/P-1n ratio. These results show the necessity of detailed understanding of the decay scheme, including data from neutron spectroscopy, in addition to gamma measurements of the multineutron emitters.
Address [Yokoyama, R.; Grzywacz, R.; Rasco, B. C.; Brewer, N.; Heideman, J.; King, T. T.; Madurga, M.; Singh, M.] Univ Tennessee, Dept Phys & Astron, Knoxville, TN 37996 USA, Email: yokoyama@cns.s.u-tokyo.ac.jp
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 2469-9985 ISBN Medium
Area Expedition Conference
Notes WOS:001159167500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5939
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Author Orrigo, S.E.A.; Tain, J.L.; Mont-Geli, N.; Tarifeño-Saldivia, A.; Fraile, L.M.; Grieger, M.; Agramunt, J.; Algora, A.; Bemmerer, D.; Calvino, F.; Cortes, G.; De Blas, A.; Dillmann, I.; Dominguez Bugarin, A.; Garcia, R.; Nacher, E.; Tolosa-Delgado, A.
Title Long-term evolution of the neutron rate at the Canfranc Underground Laboratory Type Journal Article
Year 2022 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 82 Issue 9 Pages 814 - 11pp
Keywords
Abstract We report results on the long-term variation of the neutron counting rate at the Canfranc Underground Laboratory, of importance for several low-background experiments installed there, including rare-event searches. The measurement campaign was performed employing the High Efficiency Neutron Spectrometry Array (HENSA) mounted in Hall A and lasted 412 live days. The present study is the first long-term measurement of the neutron rate with sensitivity over a wide range of neutron energies (from thermal up to 0.1 GeV and beyond) performed in any underground laboratory so far. Data on the environmental variables inside the experimental hall (radon concentration, air temperature, air pressure and humidity) were also acquired during all the measurement campaign. We have investigated for the first time the evolution of the neutron rate for different energies of the neutrons and its correlation with the ambient variables.
Address [Orrigo, S. E. A.; Tain, J. L.; Agramunt, J.; Algora, A.; Nacher, E.; Tolosa-Delgado, A.] Univ Valencia, Inst Fis Corpuscular, CSIC, Valencia 46071, Spain, Email: Sonja.Orrigo@ific.uv.es
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000853333800003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5358
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Author Cabrera, M.E.; Casas, J.A.; Delgado, A.; Robles, S.; Ruiz de Austri, R.
Title Naturalness of MSSM dark matter Type Journal Article
Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 08 Issue 8 Pages 058 - 30pp
Keywords Supersymmetry Phenomenology
Abstract There exists a vast literature examining the electroweak (EW) fine-tuning problem in supersymmetric scenarios, but little concerned with the dark matter (DM) one, which should be combined with the former. In this paper, we study this problem in an, as much as possible, exhaustive and rigorous way. We have considered the MSSM framework, assuming that the LSP is the lightest neutralino, chi(0)(1), and exploring the various possibilities for the mass and composition of chi(0)(1), as well as different mechanisms for annihilation of the DM particles in the early Universe (well-tempered neutralinos, funnels and co-annihilation scenarios). We also present a discussion about the statistical meaning of the fine-tuning and how it should be computed for the DM abundance, and combined with the EW fine-tuning. The results are very robust and model-independent and favour some scenarios (like the h-funnel when M-chi 10 is not too close to m(h)/2) with respect to others (such as the pure wino case). These features should be taken into account when one explores “natural SUSY” scenarios and their possible signatures at the LHC and in DM detection experiments.
Address [Cabrera, Maria Eugenia] Univ Sao Paulo, Inst Fis, BR-05508900 Sao Paulo, SP, Brazil, Email: mcabrera@if.usp.br;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000382166600004 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2797
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Author Chala, M.; Delgado, A.; Nardini, G.; Quiros, M.
Title A light sneutrino rescues the light stop Type Journal Article
Year 2017 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 04 Issue 4 Pages 097 - 22pp
Keywords Supersymmetry Phenomenology
Abstract Stop searches in supersymmetric frameworks with R-parity conservation usually assume the lightest neutralino to be the lightest supersymmetric particle. In this paper we consider an alternative scenario in which the left-handed tau sneutrino is lighter than neutralinos and stable at collider scales, but possibly unstable at cosmological scales. Moreover the (mostly right-handed) stop (t) over tilde is lighter than all electroweakinos, and heavier than the scalars of the third generation lepton doublet, whose charged component, (T) over tilde, is heavier than the neutral one, (v) over tilde. The remaining supersymmetric particles are decoupled from the stop phenomenology. In most of the parameter space, the relevant stop decays are only into t (T) over tildeT, t (v) over tildev and b (v) over tildeT via off-shell electroweakinos. We constrain the branching ratios of these decays by recasting the most sensitive stop searches. Due to the “double invisible” kinematics of the (t) over tilde -> t (v) over tildev process, and the low efficiency in tagging the t (T) over tildeT decay products, light stops are generically allowed. In the minimal supersymmetric standard model with similar to 100 GeV sneutrinos, stops with masses as small as similar to 350 GeV turn out to be allowed at 95% CL.
Address [Chala, M.] Univ Valencia, Dept Fis Teor, Dr Moliner 50, E-46100 Burjassot, Valencia, Spain, Email: mikael.chala@ific.uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000402858600006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3165
Permanent link to this record
 

 
Author Hall, O. et al; Agramunt, J.; Algora, A.; Domingo-Pardo, C.; Morales, A.I.; Rubio, B.; Tain, J.L.; Tolosa-Delgado, A.
Title beta-delayed neutron emission of r-process nuclei at the N=82 shell closure Type Journal Article
Year 2021 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 816 Issue Pages 136266 - 7pp
Keywords beta-delayed neutron emission; r-processimportant
Abstract Theoretical models of beta-delayed neutron emission are used as crucial inputs in r-process calculations. Benchmarking the predictions of these models is a challenge due to a lack of currently available experimental data. In this work the beta-delayed neutron emission probabilities of 33 nuclides in the important mass regions south and south-west of Sn-132 are presented, 16 for the first time. The measurements were performed at RIKEN using the Advanced Implantation Detector Array (AIDA) and the BRIKEN neutron detector array. The P-1n values presented constrain the predictions of theoretical models in the region, affecting the final abundance distribution of the second r-process peak at A approximate to 130.
Address [Hall, O.; Davinson, T.; Bruno, C. G.; Griffin, C. J.; Kahl, D.] Univ Edinburgh, Sch Phys & Astron, Edinburgh EH9 3FD, Midlothian, Scotland, Email: oscar.hall@ed.ac.uk
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000647421500016 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4819
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Author Rasco, B.C.; Brewer, N.T.; Yokoyama, R.; Grzywacz, R.; Rykaczewski, K.P.; Tolosa-Delgado, A.; Agramunt, J.; Tain, J.L.; Algora, A.; Hall, O.; Griffin, C.; Davinson, T.; Phong, V.H.; Liu, J.; Nishimura, S.; Kiss, G.G.; Nepal, N.; Estrade, A.
Title The ORNL analysis technique for extracting beta-delayed multi-neutron branching ratios with BRIKEN Type Journal Article
Year 2018 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 911 Issue Pages 79-86
Keywords Neutron detectors; Multi-neutron emission data analysis
Abstract Many choices are available in order to evaluate large radioactive decay networks. There are many parameters that influence the calculated beta-decay delayed single and multi-neutron emission branching fractions. We describe assumptions about the decay model, background, and other parameters and their influence on beta-decay delayed multi-neutron emission analysis. An analysis technique, the ORNL BRIKEN analysis procedure, for determining beta-delayed multi-neutron branching ratios in beta-neutron precursors produced by means of heavy-ion fragmentation is presented. The technique is based on estimating the initial activities of zero, one, and two neutrons occurring in coincidence with an ion-implant and beta trigger. The technique allows one to extract beta-delayed multi-neutron decay branching ratios measured with the He-3 BRIKEN neutron counter. As an example, two analyses of the beta-neutron emitter Cu-77 based on different a priori assumptions are presented along with comparisons to literature values.
Address [Rasco, B. C.; Brewer, N. T.; Rykaczewski, K. P.] Oak Ridge Natl Lab, Phys Div, Oak Ridge, TN 37831 USA, Email: brasco@utk.edu
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN (down) 0168-9002 ISBN Medium
Area Expedition Conference
Notes WOS:000450880200013 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3813
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