Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53

Z. Y. Xu; R. Grzywacz; A. Gottardo; M. Madurga; I. M. Alonso; A. N. Andreyev; G. Benzoni; M. J.G. Borge; T. Cap; C. Costache; H. De Witte; B. I. Dimitrov; J. E. Escher; A. Fijalkowska; L. M. Fraile; S. Franchoo; H. O.U. Fynbo; B. C. Gonsalves; C. J. Gross; L. J. Harkness-Brennan; J. Heideman; M. Huyse; D. S. Judson; T. Kawano; T. T. King; S. Kisyov; K. Kolos; A. Korgul; I. Lazarus; R. Licǎ; M. L. Liu; L. Lynch; N. Marginean; R. Marginean; C. Mazzocchi; D. Mengoni; C. Mihai; A. I. Morales; R. D. Page; J. Pakarinen; S. V. Paulauskas; A. Perea; M. Piersa-Siłkowska; Zs Podolyák; Ch Sotty; S. Taylor; O. Tengblad; P. Van Duppen; V. Vedia; D. Verney; N. Warr; C. X. Yuan

doi:10.1103/PhysRevLett.133.042501

Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53

Z. Y. Xu, R. Grzywacz, A. Gottardo, M. Madurga, I. M. Alonso, A. N. Andreyev, G. Benzoni, M. J.G. Borge, T. Cap, C. Costache, H. De Witte, B. I. Dimitrov, J. E. Escher, A. Fijalkowska, L. M. Fraile, S. Franchoo, H. O.U. Fynbo, B. C. Gonsalves, C. J. Gross, L. J. Harkness-BrennanJ. Heideman, M. Huyse, D. S. Judson, T. Kawano, T. T. King, S. Kisyov, K. Kolos, A. Korgul, I. Lazarus, R. Licǎ, M. L. Liu, L. Lynch, N. Marginean, R. Marginean, C. Mazzocchi, D. Mengoni, C. Mihai, A. I. Morales, R. D. Page, J. Pakarinen, S. V. Paulauskas, A. Perea, M. Piersa-Siłkowska, Zs Podolyák, Ch Sotty, S. Taylor, O. Tengblad, P. Van Duppen, V. Vedia, D. Verney, N. Warr, C. X. Yuan

Nuclear Structure and Nuclear Astrophysi

Research output: Contribution to journal › Article › peer-review

Abstract

We investigated decays of K51,52,53 at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless "compound nucleus."The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied β decay due to insufficient excitation energy and level densities in the neutron emitter. In the K53 βn decay, we found a preferential population of the first excited state in Ca52 that contradicted Bohr's hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of "compound-nucleus"decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.

Original language	English
Article number	042501
Journal	Physical Review Letters
Volume	133
Issue number	4
DOIs	https://doi.org/10.1103/PhysRevLett.133.042501
State	Published - Jul 26 2024

Funding

We acknowledge the support of the ISOLDE Collaboration and technical teams. The authors thank Dr. Sota Yoshida for valuable discussions and sharing the sdpf-sdg effective interaction . This project was supported by the European Unions Horizon 2020 research and innovation programme under the Grant Agreement No. 654002 (ENSAR2) and the Marie Sk\u0142odowska-Curie Grant Agreement No. 101032999 (BeLaPEx), by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DE-AC05-00OR22725 (ORNL), by the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory under Contract No. 89233218CNA000001, by the auspices of the U.S. Department of Energy at Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344, by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-436NA0003899, No. DE-NA0002132, and No. DE-NA0004068, by the Romanian IFA grant CERN/ISOLDE and Nucleu Project No. PN 23 21 01 02, by the Research Foundation Flanders (FWO, Belgium) and by BOF KU Leuven (C14/22/104), by the German BMBF under Contracts No. 05P18PKCIA and No. 05P21PKCI1 in Verbundprojekte 05P2018 and 05P2021, by the UK Science and Technology Facilities Research Council (STFC) of the UK Grants No. ST/R004056/1, No. ST/P004598/1, No. ST/P003885/1, No. ST/V001027/1, and No. ST/V001035/1, by the Guangdong Major Project of Basic and Applied Basic Research under Grant No. 2021B0301030006, by the Polish National Science Center under Grant No. 2020/39/B/ST2/02346, by the Polish Ministry of Education and Science under Contract No. 2021/WK/07, by Spanish MCIN/AEI/10.13039/501100011033 under Grants No. PGC2018-093636-B-I00, No. RTI2018-098868-B-I00, No. PID2019-104390 GB-I00, No. PID2019-104714 GB-C21, No. PID2021-126998OB-I00, and No. PID2022-140162NB-I00, by Generalitat Valenciana, Conselleria de Innovaci\u00F3n, Universidades, Ciencia y Sociedad Digital under Grant No. CISEJI/2022/25, and by Universidad Complutense de Madrid (Spain) through Grupo de F\u00EDsica Nuclear (910059). The shell-model LD were calculated with kshell . The doorway-state energies and spectroscopic factors were obtained from n u s hell x @ msu . The Hauser-Feshbach calculations were done using the b eo h code . We acknowledge the support of the ISOLDE Collaboration and technical teams. The authors thank Dr. Sota Yoshida for valuable discussions and sharing the sdpf-sdg effective interaction. This project was supported by the European Unions Horizon 2020 research and innovation programme under the Grant Agreement No. 654002 (ENSAR2) and the Marie Sklodowska-Curie Grant Agreement No. 101032999 (BeLaPEx), by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DE-AC05-00OR22725 (ORNL), by the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory under Contract No. 89233218CNA000001, by the auspices of the U.S. Department of Energy at Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344, by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-436NA0003899, No. DE-NA0002132, and No. DE-NA0004068, by the Romanian IFA grant CERN/ISOLDE and Nucleu Project No. PN 23 21 01 02, by the Research Foundation Flanders (FWO, Belgium) and by BOF KU Leuven (C14/22/104), by the German BMBF under Contracts No. 05P18PKCIA and No. 05P21PKCI1 in Verbundprojekte 05P2018 and 05P2021, by the UK Science and Technology Facilities Research Council (STFC) of the UK Grants No. ST/R004056/1, No. ST/P004598/1, No. ST/P003885/1, No. ST/V001027/1, and No. ST/V001035/1, by the Guangdong Major Project of Basic and Applied Basic Research under Grant No. 2021B0301030006, by the Polish National Science Center under Grant No. 2020/39/B/ST2/02346, by the Polish Ministry of Education and Science under Contract No. 2021/WK/07, by Spanish MCIN/AEI/10.13039/501100011033 under Grants No. PGC2018-093636-B-I00, No. RTI2018-098868-B-I00, No. PID2019-104390GB-I00, No. PID2019-104714GB-C21, No. PID2021-126998OB-I00, and No. PID2022-140162NB-I00, by Generalitat Valenciana, Conselleria de Innovacien, Universidades, Ciencia y Sociedad Digital under Grant No. CISEJI/2022/25, and by Universidad Complutense de Madrid (Spain) through Grupo de Fisica Nuclear (910059). The shell-model LD were calculated with kshell. The doorway-state energies and spectroscopic factors were obtained from nushellx@msu. The Hauser-Feshbach calculations were done using the beoh code.

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10.1103/PhysRevLett.133.042501

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Xu, Z. Y., Grzywacz, R., Gottardo, A., Madurga, M., Alonso, I. M., Andreyev, A. N., Benzoni, G., Borge, M. J. G., Cap, T., Costache, C., De Witte, H., Dimitrov, B. I., Escher, J. E., Fijalkowska, A., Fraile, L. M., Franchoo, S., Fynbo, H. O. U., Gonsalves, B. C., Gross, C. J., ... Yuan, C. X. (2024). Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53. Physical Review Letters, 133(4), Article 042501. https://doi.org/10.1103/PhysRevLett.133.042501

@article{cef76fd0475b48b2bb2ea3ad0016b56f,

title = "Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53",

abstract = "We investigated decays of K51,52,53 at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless {"}compound nucleus.{"}The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied β decay due to insufficient excitation energy and level densities in the neutron emitter. In the K53 βn decay, we found a preferential population of the first excited state in Ca52 that contradicted Bohr's hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of {"}compound-nucleus{"}decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.",

author = "Xu, {Z. Y.} and R. Grzywacz and A. Gottardo and M. Madurga and Alonso, {I. M.} and Andreyev, {A. N.} and G. Benzoni and Borge, {M. J.G.} and T. Cap and C. Costache and {De Witte}, H. and Dimitrov, {B. I.} and Escher, {J. E.} and A. Fijalkowska and Fraile, {L. M.} and S. Franchoo and Fynbo, {H. O.U.} and Gonsalves, {B. C.} and Gross, {C. J.} and Harkness-Brennan, {L. J.} and J. Heideman and M. Huyse and Judson, {D. S.} and T. Kawano and King, {T. T.} and S. Kisyov and K. Kolos and A. Korgul and I. Lazarus and R. Licǎ and Liu, {M. L.} and L. Lynch and N. Marginean and R. Marginean and C. Mazzocchi and D. Mengoni and C. Mihai and Morales, {A. I.} and Page, {R. D.} and J. Pakarinen and Paulauskas, {S. V.} and A. Perea and M. Piersa-Si{\l}kowska and Zs Podoly{\'a}k and Ch Sotty and S. Taylor and O. Tengblad and {Van Duppen}, P. and V. Vedia and D. Verney and N. Warr and Yuan, {C. X.}",

note = "Publisher Copyright: {\textcopyright} 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the {"}https://creativecommons.org/licenses/by/4.0/{"}Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by CERN.",

year = "2024",

month = jul,

day = "26",

doi = "10.1103/PhysRevLett.133.042501",

language = "English",

volume = "133",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "4",

}

Xu, ZY, Grzywacz, R, Gottardo, A, Madurga, M, Alonso, IM, Andreyev, AN, Benzoni, G, Borge, MJG, Cap, T, Costache, C, De Witte, H, Dimitrov, BI, Escher, JE, Fijalkowska, A, Fraile, LM, Franchoo, S, Fynbo, HOU, Gonsalves, BC, Gross, CJ, Harkness-Brennan, LJ, Heideman, J, Huyse, M, Judson, DS, Kawano, T, King, TT, Kisyov, S, Kolos, K, Korgul, A, Lazarus, I, Licǎ, R, Liu, ML, Lynch, L, Marginean, N, Marginean, R, Mazzocchi, C, Mengoni, D, Mihai, C, Morales, AI, Page, RD, Pakarinen, J, Paulauskas, SV, Perea, A, Piersa-Siłkowska, M, Podolyák, Z, Sotty, C, Taylor, S, Tengblad, O, Van Duppen, P, Vedia, V, Verney, D, Warr, N & Yuan, CX 2024, 'Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53', Physical Review Letters, vol. 133, no. 4, 042501. https://doi.org/10.1103/PhysRevLett.133.042501

TY - JOUR

T1 - Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53

AU - Xu, Z. Y.

AU - Grzywacz, R.

AU - Gottardo, A.

AU - Madurga, M.

AU - Alonso, I. M.

AU - Andreyev, A. N.

AU - Benzoni, G.

AU - Borge, M. J.G.

AU - Cap, T.

AU - Costache, C.

AU - De Witte, H.

AU - Dimitrov, B. I.

AU - Escher, J. E.

AU - Fijalkowska, A.

AU - Fraile, L. M.

AU - Franchoo, S.

AU - Fynbo, H. O.U.

AU - Gonsalves, B. C.

AU - Gross, C. J.

AU - Harkness-Brennan, L. J.

AU - Heideman, J.

AU - Huyse, M.

AU - Judson, D. S.

AU - Kawano, T.

AU - King, T. T.

AU - Kisyov, S.

AU - Kolos, K.

AU - Korgul, A.

AU - Lazarus, I.

AU - Licǎ, R.

AU - Liu, M. L.

AU - Lynch, L.

AU - Marginean, N.

AU - Marginean, R.

AU - Mazzocchi, C.

AU - Mengoni, D.

AU - Mihai, C.

AU - Morales, A. I.

AU - Page, R. D.

AU - Pakarinen, J.

AU - Paulauskas, S. V.

AU - Perea, A.

AU - Piersa-Siłkowska, M.

AU - Podolyák, Zs

AU - Sotty, Ch

AU - Taylor, S.

AU - Tengblad, O.

AU - Van Duppen, P.

AU - Vedia, V.

AU - Verney, D.

AU - Warr, N.

AU - Yuan, C. X.

N1 - Publisher Copyright: © 2024 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by CERN.

PY - 2024/7/26

Y1 - 2024/7/26

N2 - We investigated decays of K51,52,53 at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless "compound nucleus."The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied β decay due to insufficient excitation energy and level densities in the neutron emitter. In the K53 βn decay, we found a preferential population of the first excited state in Ca52 that contradicted Bohr's hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of "compound-nucleus"decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.

AB - We investigated decays of K51,52,53 at the ISOLDE Decay Station at CERN in order to understand the mechanism of the β-delayed neutron-emission (βn) process. The experiment quantified neutron and γ-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the βn process originate from the structureless "compound nucleus."The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied β decay due to insufficient excitation energy and level densities in the neutron emitter. In the K53 βn decay, we found a preferential population of the first excited state in Ca52 that contradicted Bohr's hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of "compound-nucleus"decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.

UR - http://www.scopus.com/inward/record.url?scp=85199433373&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.133.042501

DO - 10.1103/PhysRevLett.133.042501

M3 - Article

AN - SCOPUS:85199433373

SN - 0031-9007

VL - 133

JO - Physical Review Letters

JF - Physical Review Letters

IS - 4

M1 - 042501

ER -

Compound-Nucleus and Doorway-State Decays of β -Delayed Neutron Emitters K 51,52,53

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