Effective proton-neutron interaction near the drip line from unbound states in 25,26 F

M. Vandebrouck; A. Lepailleur; O Sorlin; T. Aumann; C. Caesar; M. Holl; V. Panin; F. Wamers; S. R. Stroberg; J. D. Holt; F. De Oliveira Santos; H. Alvarez-Pol; L. Atar; V. Avdeichikov; S. Beceiro-Novo; D. Bemmerer; J. Benlliure; C. A. Bertulani; S. K. Bogner; J. M. Boillos; K. Boretzky; M. J. G. Borge; M. Caamaño; E. Casarejos; W Catford; J. Cederkäll; M. Chartier; L. V. Chulkov; D Cortina-Gil; E. Cravo; R. Crespo; U. Datta Pramanik; P. Díaz Fernández; I. Dillmann; Z. Elekes; J. Enders; O. Ershova; A. Estradé; F. Farinon; L. M. Fraile; M. Freer; D. Galaviz; H Geissel; R. Gernhäuser; J. Gibelin; P. Golubev; K. Göbel; J. Hagdahl; S. Paschalis; M. Petri; R3B collaboration

doi:10.1103/PhysRevC.96.054305

Effective proton-neutron interaction near the drip line from unbound states in 25,26 F

M. Vandebrouck, A. Lepailleur, O Sorlin, T. Aumann, C. Caesar, M. Holl, V. Panin, F. Wamers, S. R. Stroberg, J. D. Holt, F. De Oliveira Santos, H. Alvarez-Pol, L. Atar, V. Avdeichikov, S. Beceiro-Novo, D. Bemmerer, J. Benlliure, C. A. Bertulani, S. K. Bogner, J. M. BoillosK. Boretzky, M. J. G. Borge, M. Caamaño, E. Casarejos, W Catford, J. Cederkäll, M. Chartier, L. V. Chulkov, D Cortina-Gil, E. Cravo, R. Crespo, U. Datta Pramanik, P. Díaz Fernández, I. Dillmann, Z. Elekes, J. Enders, O. Ershova, A. Estradé, F. Farinon, L. M. Fraile, M. Freer, D. Galaviz, H Geissel, R. Gernhäuser, J. Gibelin, P. Golubev, K. Göbel, J. Hagdahl, S. Paschalis, M. Petri, R3B collaboration

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Abstract

Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F26 nucleus, composed of a deeply bound π0d5/2 proton and an unbound ν0d3/2 neutron on top of an O24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a Jπ=11+-41+ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The Jπ=11+,21+,41+ bound states have been determined, and only a clear identification of the Jπ=31+ is missing. Purpose: We wish to complete the study of the Jπ=11+-41+ multiplet in F26, by studying the energy and width of the Jπ=31+ unbound state. The method was first validated by the study of unbound states in F25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne26 and Ne27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F25 and F26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the R3B/LAND setup. The detection of emitted γ rays and neutrons, added to the reconstruction of the momentum vector of the A-1 nuclei, allowed the determination of the energy of three unbound states in F25 and two in F26. Results: Based on its width and decay properties, the first unbound state in F25, at the relative energy of 49(9) keV, is proposed to be a Jπ=1/2- arising from a p1/2 proton-hole state. In F26, the first resonance at 323(33) keV is proposed to be the Jπ=31+ member of the Jπ=11+-41+ multiplet. Energies of observed states in F25,26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F26.

Original language	English
Article number	054305
Number of pages	13
Journal	Physical Review C
Volume	96
Issue number	5
DOIs	https://doi.org/10.1103/PhysRevC.96.054305
Publication status	Published - 8 Nov 2017

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PhysRevC.96.054305
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Vandebrouck, M., Lepailleur, A., Sorlin, O., Aumann, T., Caesar, C., Holl, M., Panin, V., Wamers, F., Stroberg, S. R., Holt, J. D., De Oliveira Santos, F., Alvarez-Pol, H., Atar, L., Avdeichikov, V., Beceiro-Novo, S., Bemmerer, D., Benlliure, J., Bertulani, C. A., Bogner, S. K., ... R3B collaboration (2017). Effective proton-neutron interaction near the drip line from unbound states in 25,26 F. Physical Review C, 96(5), Article 054305. https://doi.org/10.1103/PhysRevC.96.054305

@article{982bdd4a0b7447d19ae97a725a884c9b,

title = "Effective proton-neutron interaction near the drip line from unbound states in 25,26 F",

abstract = "Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F26 nucleus, composed of a deeply bound π0d5/2 proton and an unbound ν0d3/2 neutron on top of an O24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a Jπ=11+-41+ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The Jπ=11+,21+,41+ bound states have been determined, and only a clear identification of the Jπ=31+ is missing. Purpose: We wish to complete the study of the Jπ=11+-41+ multiplet in F26, by studying the energy and width of the Jπ=31+ unbound state. The method was first validated by the study of unbound states in F25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne26 and Ne27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F25 and F26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the R3B/LAND setup. The detection of emitted γ rays and neutrons, added to the reconstruction of the momentum vector of the A-1 nuclei, allowed the determination of the energy of three unbound states in F25 and two in F26. Results: Based on its width and decay properties, the first unbound state in F25, at the relative energy of 49(9) keV, is proposed to be a Jπ=1/2- arising from a p1/2 proton-hole state. In F26, the first resonance at 323(33) keV is proposed to be the Jπ=31+ member of the Jπ=11+-41+ multiplet. Energies of observed states in F25,26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F26.",

author = "M. Vandebrouck and A. Lepailleur and O Sorlin and T. Aumann and C. Caesar and M. Holl and V. Panin and F. Wamers and Stroberg, {S. R.} and Holt, {J. D.} and {De Oliveira Santos}, F. and H. Alvarez-Pol and L. Atar and V. Avdeichikov and S. Beceiro-Novo and D. Bemmerer and J. Benlliure and Bertulani, {C. A.} and Bogner, {S. K.} and Boillos, {J. M.} and K. Boretzky and Borge, {M. J. G.} and M. Caama{\~n}o and E. Casarejos and W Catford and J. Cederk{\"a}ll and M. Chartier and Chulkov, {L. V.} and D Cortina-Gil and E. Cravo and R. Crespo and {Datta Pramanik}, U. and {D{\'i}az Fern{\'a}ndez}, P. and I. Dillmann and Z. Elekes and J. Enders and O. Ershova and A. Estrad{\'e} and F. Farinon and Fraile, {L. M.} and M. Freer and D. Galaviz and H Geissel and R. Gernh{\"a}user and J. Gibelin and P. Golubev and K. G{\"o}bel and J. Hagdahl and S. Paschalis and M. Petri and {R3B collaboration}",

note = "{\textcopyright}2017 American Physical Society. Uploaded in accordance with the publisher{\textquoteright}s self-archiving policy. Further copying may not be permitted; contact the publisher for details. ",

year = "2017",

month = nov,

day = "8",

doi = "10.1103/PhysRevC.96.054305",

language = "English",

volume = "96",

journal = "Physical Review C",

issn = "2469-9985",

publisher = "American Physical Society",

number = "5",

}

Vandebrouck, M, Lepailleur, A, Sorlin, O, Aumann, T, Caesar, C, Holl, M, Panin, V, Wamers, F, Stroberg, SR, Holt, JD, De Oliveira Santos, F, Alvarez-Pol, H, Atar, L, Avdeichikov, V, Beceiro-Novo, S, Bemmerer, D, Benlliure, J, Bertulani, CA, Bogner, SK, Boillos, JM, Boretzky, K, Borge, MJG, Caamaño, M, Casarejos, E, Catford, W, Cederkäll, J, Chartier, M, Chulkov, LV, Cortina-Gil, D, Cravo, E, Crespo, R, Datta Pramanik, U, Díaz Fernández, P, Dillmann, I, Elekes, Z, Enders, J, Ershova, O, Estradé, A, Farinon, F, Fraile, LM, Freer, M, Galaviz, D, Geissel, H, Gernhäuser, R, Gibelin, J, Golubev, P, Göbel, K, Hagdahl, J, Paschalis, S , Petri, M & R3B collaboration 2017, 'Effective proton-neutron interaction near the drip line from unbound states in 25,26 F', Physical Review C, vol. 96, no. 5, 054305. https://doi.org/10.1103/PhysRevC.96.054305

TY - JOUR

T1 - Effective proton-neutron interaction near the drip line from unbound states in 25,26 F

AU - Vandebrouck, M.

AU - Lepailleur, A.

AU - Sorlin, O

AU - Aumann, T.

AU - Caesar, C.

AU - Holl, M.

AU - Panin, V.

AU - Wamers, F.

AU - Stroberg, S. R.

AU - Holt, J. D.

AU - De Oliveira Santos, F.

AU - Alvarez-Pol, H.

AU - Atar, L.

AU - Avdeichikov, V.

AU - Beceiro-Novo, S.

AU - Bemmerer, D.

AU - Benlliure, J.

AU - Bertulani, C. A.

AU - Bogner, S. K.

AU - Boillos, J. M.

AU - Boretzky, K.

AU - Borge, M. J. G.

AU - Caamaño, M.

AU - Casarejos, E.

AU - Catford, W

AU - Cederkäll, J.

AU - Chartier, M.

AU - Chulkov, L. V.

AU - Cortina-Gil, D

AU - Cravo, E.

AU - Crespo, R.

AU - Datta Pramanik, U.

AU - Díaz Fernández, P.

AU - Dillmann, I.

AU - Elekes, Z.

AU - Enders, J.

AU - Ershova, O.

AU - Estradé, A.

AU - Farinon, F.

AU - Fraile, L. M.

AU - Freer, M.

AU - Galaviz, D.

AU - Geissel, H

AU - Gernhäuser, R.

AU - Gibelin, J.

AU - Golubev, P.

AU - Göbel, K.

AU - Hagdahl, J.

AU - Paschalis, S.

AU - Petri, M.

AU - R3B collaboration

PY - 2017/11/8

Y1 - 2017/11/8

N2 - Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F26 nucleus, composed of a deeply bound π0d5/2 proton and an unbound ν0d3/2 neutron on top of an O24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a Jπ=11+-41+ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The Jπ=11+,21+,41+ bound states have been determined, and only a clear identification of the Jπ=31+ is missing. Purpose: We wish to complete the study of the Jπ=11+-41+ multiplet in F26, by studying the energy and width of the Jπ=31+ unbound state. The method was first validated by the study of unbound states in F25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne26 and Ne27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F25 and F26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the R3B/LAND setup. The detection of emitted γ rays and neutrons, added to the reconstruction of the momentum vector of the A-1 nuclei, allowed the determination of the energy of three unbound states in F25 and two in F26. Results: Based on its width and decay properties, the first unbound state in F25, at the relative energy of 49(9) keV, is proposed to be a Jπ=1/2- arising from a p1/2 proton-hole state. In F26, the first resonance at 323(33) keV is proposed to be the Jπ=31+ member of the Jπ=11+-41+ multiplet. Energies of observed states in F25,26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F26.

AB - Background: Odd-odd nuclei, around doubly closed shells, have been extensively used to study proton-neutron interactions. However, the evolution of these interactions as a function of the binding energy, ultimately when nuclei become unbound, is poorly known. The F26 nucleus, composed of a deeply bound π0d5/2 proton and an unbound ν0d3/2 neutron on top of an O24 core, is particularly adapted for this purpose. The coupling of this proton and neutron results in a Jπ=11+-41+ multiplet, whose energies must be determined to study the influence of the proximity of the continuum on the corresponding proton-neutron interaction. The Jπ=11+,21+,41+ bound states have been determined, and only a clear identification of the Jπ=31+ is missing. Purpose: We wish to complete the study of the Jπ=11+-41+ multiplet in F26, by studying the energy and width of the Jπ=31+ unbound state. The method was first validated by the study of unbound states in F25, for which resonances were already observed in a previous experiment. Method: Radioactive beams of Ne26 and Ne27, produced at about 440AMeV by the fragment separator at the GSI facility were used to populate unbound states in F25 and F26 via one-proton knockout reactions on a CH2 target, located at the object focal point of the R3B/LAND setup. The detection of emitted γ rays and neutrons, added to the reconstruction of the momentum vector of the A-1 nuclei, allowed the determination of the energy of three unbound states in F25 and two in F26. Results: Based on its width and decay properties, the first unbound state in F25, at the relative energy of 49(9) keV, is proposed to be a Jπ=1/2- arising from a p1/2 proton-hole state. In F26, the first resonance at 323(33) keV is proposed to be the Jπ=31+ member of the Jπ=11+-41+ multiplet. Energies of observed states in F25,26 have been compared to calculations using the independent-particle shell model, a phenomenological shell model, and the ab initio valence-space in-medium similarity renormalization group method. Conclusions: The deduced effective proton-neutron interaction is weakened by about 30-40% in comparison to the models, pointing to the need for implementing the role of the continuum in theoretical descriptions or to a wrong determination of the atomic mass of F26.

UR - http://www.scopus.com/inward/record.url?scp=85033794918&partnerID=8YFLogxK

U2 - 10.1103/PhysRevC.96.054305

DO - 10.1103/PhysRevC.96.054305

M3 - Article

AN - SCOPUS:85033794918

SN - 2469-9985

VL - 96

JO - Physical Review C

JF - Physical Review C

IS - 5

M1 - 054305

ER -

Effective proton-neutron interaction near the drip line from unbound states in 25,26 F

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