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1. Evolution of single-particle strength in neutron-rich 71Cu

Author

P. Morfouace, S. Franchoo, K. Sieja, I. Matea, L. Nalpas, M. Niikura, A.M. Sánchez-Benítez, I. Stefan, M. Assié, F. Azaiez, D. Beaumel, S. Boissinot, C. Borcea, R. Borcea, G. Burgunder, L. Cáceres, N. De Séréville, Zs. Dombrádi, J. Elseviers, B. Fernández-Domínguez, A. Gillibert, S. Giron, S. Grévy, F. Hammache, O. Kamalou, V. Lapoux, L. Lefebvre, A. Lepailleur, C. Louchart, G. Marquinez-Duran, I. Martel, A. Matta, D. Mengoni, D.R. Napoli, F. Recchia, J.-A. Scarpaci, D. Sohler, O. Sorlin, M. Stanoiu, C. Stodel, J.-C. Thomas, and Zs. Vajta

Subjects
Physics, QC1-999
Abstract

The strength functions of the πf5/2, πp3/2 and πf7/2 orbitals in neutron-rich 71Cu were obtained in a 72Zn(d,3He)71Cu proton pick-up reaction in inverse kinematics using a radioactive beam of 72Zn at 38 MeV/u. A dedicated set-up was developed to overcome the experimental challenges posed by the low cross section of the reaction and the low energy of the outgoing 3He particles. The excitation-energy spectrum was reconstructed and spectroscopic factors were obtained after analysis of the angular distributions with the finite-range Distorted-Wave Born Approximation (DWBA). The results show that unlike for the πf5/2 orbital and contrary to earlier interpretation, the πf7/2 single-particle strength distribution is not appreciably affected by the addition of neutrons beyond N=40.

Published
2015
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2. Solid hydrogen target for missing mass spectroscopy in inverse kinematics

Author

Yohei Matsuda, Juzo Zenihiro, Zhengyang Tian, Harutaka Sakaguchi, Nori Aoi, S. Kawakami, Satoru Terashima, Yukie Maeda, Takahiro Kawabata, M. Tsumura, D. Beaumel, Tetsuya Yamamoto, S. Gotanda, and Hideaki Otsu

Subjects
Radioactive ion beams, Elastic scattering, Inverse kinematics, Chemistry, Health, Toxicology and Mutagenesis, Public Health, Environmental and Occupational Health, Mechanical press, Mass spectrometry, Spin isomers of hydrogen, Pollution, Analytical Chemistry, Neodymium magnet, Nuclear Energy and Engineering, Solid hydrogen, Radiology, Nuclear Medicine and imaging, Atomic physics, Spectroscopy
Abstract

By using para-hydrogen and a mechanical press made of neodymium magnets, we have succeeded in making a 1-mm-thick and 30-mm-diameter solid hydrogen target (SHT), and have measured elastic scattering of protons with radioactive ion beams at 300 MeV/u. We also succeeded in making not only a 0.5-mm-thick and 10-mm-diameter SHT but also a 2-mm-thick and 30-mm-diameter SHT to study excited-state properties of nuclei via (p,p′) reactions, and quasi-free (p,pα) reactions at intermediate energies. The ortho–para converter and the simple mechanical press show possibilities for making SHTs which have various radii and thicknesses.

Published
2015
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3. Identification of light particles by means of pulse shape analysis with silicon detector at low energy

Author

V. V. Parkar, Ismael Martel, J.A. Dueñas, M. Assié, R. Berjillos, A. M. Sánchez-Benítez, D. Beaumel, D. Mengoni, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Photon, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Preamplifier, business.industry, Doping, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Particle identification, Charged particle, Optics, 0103 physical sciences, Physics::Accelerator Physics, Neutron, Nuclear Experiment, 010306 general physics, business, Instrumentation, Beam (structure)
Abstract

Particle separation of 1,2,3H at energy of 3 MeV has been achieved by digital pule shape analysis (DPSA) for particles fully stopped in a 500 μ m silicon detector. Light charged particles were produced in a nuclear reaction induced by a 34 MeV beam of 7Li impinging on a 12C target. Proton–deuterium identification has also been observed at 2 MeV using mono-energetic beams. A 20 keV resolution neutron transmutation doped (NTD) silicon detector was employed in a low-field injection setup. The method uses the parameters obtained both from the charge and current pulses generated by a high bandwidth charge sensitive preamplifier. The simplicity of the electronic chain plus the experimental conditions allowed the team to work with very low noise achieving signal-to-noise ratio (SNR) at values greater than 10.

Published
2012
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4. PROBING PRE-FORMED ALPHA PARTICLES IN THE GROUND STATE OF NUCLEI

Author

J. A. Scarpaci, M. Fallot, Denis Lacroix, J.L. Laville, A. Chbihi, D. Beaumel, J.D. Frankland, E. Plagnol, Ph. Chomaz, J.C. Roynette, P. Roussel-Chomaz, M. Assié, P. Désesquelle, Y. Blumenfeld, C. Bhar, T. Zerguerras, H. Idbarkach, Elias Khan, A. Shrivastava, E. C. Pollacco, N. Frascaria, L. Lefebvre, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-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), CSNSM SNO, Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Département d'Electronique, des Détecteurs et d'Informatique pour la Physique (ex SEDI) (DEDIP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire SUBATECH Nantes (SUBATECH), Mines Nantes (Mines Nantes)-Université de Nantes (UN)-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)-Université Paris-Saclay, APC - Cosmologie, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-AstroParticule et Cosmologie (APC (UMR_7164)), 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)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), CEA/DSM Centre de Saclay (CEA/DSM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Nantes (UN)-Mines Nantes (Mines Nantes), 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), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)-Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Normandie Université (NU)-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)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-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)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, General Physics and Astronomy, Alpha particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear Theory (nucl-th), Angular distribution, medicine.anatomical_structure, Helium-4, 0103 physical sciences, medicine, Alpha decay, Nuclear Experiment (nucl-ex), Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Nucleus
Abstract

In this Letter, we report on alpha particle emission through the nuclear break-up in the reaction 40Ca on a 40Ca target at 50A MeV. It is observed that, similarly to nucleons, alpha particles can be emitted to the continuum with very specific angular distribution during the reaction. The alpha particle properties can be understood as resulting from an alpha cluster in the daughter nucleus that is perturbed by the short range nuclear attraction of the collision partner and emitted. A time-dependent theory that describe the alpha particle wave-function evolution is able to reproduce qualitatively the observed angular distribution. This mechanism offers new possibilities to study alpha particle properties in the nuclear medium., Comment: 4 pages, 3 figures

Published
2011
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5. Shell evolution in light nuclei inferred from transfer reactions

Author

D. Beaumel, Institut de Physique Nucléaire d'Orsay (IPNO), and Université Paris-Sud - Paris 11 (UP11)-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, Light nucleus, Quenching (fluorescence), 010308 nuclear & particles physics, Nuclear Theory, Shell (structure), chemistry.chemical_element, Germanium, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Transfer (group theory), medicine.anatomical_structure, chemistry, 0103 physical sciences, medicine, Particle, Atomic physics, Nuclear Experiment, 010306 general physics, Nucleus, Excitation
Abstract

Recent results on shell evolution in light exotic nuclei obtained through experiments performed at GANIL using the MUST2 particle array are reported. The one-nucleon transfer reactions 20 O(d,t) was investigated using a setup combining the MUST2 and TIARA particle arrays, together with EXOGAM germanium detectors. Preliminary results on the populated states as well as comparison with calculated spectroscopic factors are presented. In a second study, the Z = 8 shell closure was investigated by means of the two-neutron transfer reaction 14 O(p,t) using a set of MUST2 telescopes. A newly observed state at low excitation energy in the unbound 12 O points to the Z = 8 shell quenching, analogously to the established case at N = 8 in the neutron-rich mirror nucleus 12 Be.

Published
2010
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6. Indirect study of 19Ne states near the threshold

Author

N. de Séréville, B. Bouzid, Marc Loiselet, Jürgen Kiener, Carmen Angulo, Vincent Tatischeff, A. Coc, Michel Gaelens, P. Figuera, F. de Oliveira Santos, Guido Ryckewaert, Daniel Labar, Alain Ninane, S. Fortier, S. Ouichaoui, P. Demaret, Marlete Assunção, S. Cherubini, F. Hammache, Pierre Leleux, E. Berthoumieux, D. Beaumel, N. Smirnova, Manoel Couder, and A. Lefebvre-Schuhl

Subjects
Physics, Reaction rate, Nuclear reaction, Nuclear and High Energy Physics, Proton, 010308 nuclear & particles physics, Scattering, 0103 physical sciences, Atomic physics, 010306 general physics, 01 natural sciences, Radioactive beam
Abstract

The early E ⩽ 511 keV gamma-ray emission from novae depends critically on the F 18 ( p , α ) O 15 reaction. Unfortunately the reaction rate of the F 18 ( p , α ) O 15 reaction is still largely uncertain due to the unknown strengths of low-lying proton resonances near the F 18 + p threshold which play an important role in the nova temperature regime. We report here our last results concerning the study of the d ( F 18 , p ) F 19 ( α ) N 15 transfer reaction. We show in particular that these two low-lying resonances cannot be neglected. These results are then used to perform a careful study of the remaining uncertainties associated to the F 18 ( p , α ) O 15 and F 18 ( p , γ ) Ne 19 reaction rates.

Published
2007
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7. Low-lying states and structure of the exotic 8He via direct reactions on the proton

Author

F. Skaza, A. Gillibert, R. Wolski, D. Beaumel, A. Drouart, J. L. Sida, K. Rusek, V. Lapoux, P. Roussel-Chomaz, A. Pakou, N. Keeley, F. Auger, Lydie Giot, J.A. Scarpaci, E. Becheva, Y. Blumenfeld, E. C. Pollacco, N. Alamanos, Elias Khan, R. Raabe, S. V. Stepantsov, F. Delaunay, L. Nalpas, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-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), Peter von Neumann-Cosel, Thomas Aumann, 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, Proton, 010308 nuclear & particles physics, Scattering, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Resonance (particle physics), Charged particle, medicine.anatomical_structure, Excited state, 0103 physical sciences, medicine, Atomic physics, Nuclear Experiment, 010306 general physics, Ground state, Nucleus, Excitation
Abstract

The structure of the light exotic nucleus 8 He was investigated using direct reactions of the 8 He SPIRAL beam on a proton-rich target. The (p,p') scattering to the 2 1 + state, the (p,d) 7 He and (p,t) 6 He transfer reactions, were measured at the energy E l a b = 15.7 A.MeV . The light charged particles (p,d,t) were detected in the MUST Si-strip telescope array. The excitation spectrum of 8 He was extracted from the (p,p') reaction. Above the known 2 1 + excited state at 3.6 MeV, a second resonance was found around 5.4 MeV. The cross sections were analyzed within the coupled-reaction channels framework, using microscopic potentials. It is inferred that the 8 He ground state has a more complex neutron-skin structure than suggested by previous α + 4 n models assuming a pure ( 1 p 3 / 2 ) 4 configuration.

Published
2007
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8. Study of the N = 28 shell closure in the Ar isotopic chain

Author

E. Rich, Zsolt Dombrádi, D. Sohler, L. Nalpas, Karl Kratz, Yu. E. Penionzhkevich, J. Gibelin, F. Hammache, S. Franchoo, J.A. Scarpaci, M. Gelin, D. Beaumel, K. W. Kemper, E. C. Pollacco, S. Grévy, S. Fortier, M. Stanoiu, Thomas Rauscher, M. G. St. Laurent, Y. Blumenfeld, F. Nowacki, P. Roussel-Chomaz, O. Sorlin, A. N. Ostrowski, L. Gaudefroy, Erik Tryggestad, S. M. Lukyanov, D. Verney, F. Ibrahim, C. Monrozeau, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), 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), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), SPIRAL, Université Paris-Sud - Paris 11 (UP11)-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 and High Energy Physics, Nuclear Theory, Hadron, 21.10.Hw, 21.10.Jx, 25.60.Je, 26.30.+k, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Reaction rate, Spin, Transfer reactions, Atomic orbital, 0103 physical sciences, Nuclear astrophysics, medicine, Astrophysics::Solar and Stellar Astrophysics, Nuclear fusion, Neutron, Nuclear Experiment, 010306 general physics, Physics, 010308 nuclear & particles physics, Nucleosynthesis in novae, and isobaric spin, Neutron capture, medicine.anatomical_structure, parity, Physics::Space Physics, Spectroscopic factors, Atomic physics, supernovae and other explosive environments, Nucleus
Abstract

Expérience au GANIL NESTER; The structure of the neutron-rich nucleus $^{47}$Ar has been investigated through the d( $^{46}$Ar, $^{47}$Ar)p transfer reaction. The radioactive beam of $^{46}$Ar at 10A·MeV was provided by the SPIRAL facility at GANIL. The protons corresponding to a neutron pick-up on bound or unbound states mechanism in $^{47}$Ar nuclei were detected at backward angles by the position-sensitive Si array-detector MUST. The transfer-like ejectiles were detected in the SPEG spectrometer. Level scheme, spin assignments and spectroscopic factors have been deduced for $^{47}$Ar and compared to shell model predictions. They suggest a slight erosion of the N = 28 shell gap from the weakening of the spin-orbit interaction arising from the f and p orbitals. These spectroscopic information are subsequently used to infer (n,$\gamma$) reaction rates in the Ar isotopic chain to understand the origin of the $^{48}$Ca/ $^{46}$Ca abnormal isotopic ratio observed in certain inclusions of meteorites.

Published
2006
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9. Analysis of the 11B(7Li,7Be)11Be reaction at 57 MeV in a microscopic approach

Author

Francesco Cappuzzello, H. Lenske, Js Winfield, A. Cunsolo, A. Foti, S. Fortier, Sea Orrigo, D. Beaumel, A. Lazzaro, and C. Nociforo

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Isovector, 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Dipole, Excited state, 0103 physical sciences, Neutron, Born approximation, Atomic physics, Nuclear Experiment, 010306 general physics, Random phase approximation, Ground state
Abstract

The 11B(7Li, 7Be)11Be charge exchange reaction has been studied at an incident energy of 57 MeV. Spectra were measured at forward angles, θcm⩽35°. The good energy resolution (∼50 keV) allowed the identification of transitions both to the 7Be (3/2−, gs) and 7Be(1/2−, 429 keV) exit channels and hence the direct measurement of the ratio of the respective cross sections and angular distributions. Besides the bound ground and first excited state of 11Be several low lying excitations just above the neutron threshold are observed. A structure seen at E ∗ =9.4 MeV with FWHM ∼7 MeV is compatible with the spin dipole resonance (SDR). The data are analysed in a many-body approach. For the projectile transitions shell model results are used. In order to account properly for the special features of the weakly bound 11Be system the target transitions are described microscopically by Hartree–Fock–Bogoliubov (HFB) and quasi-particle random phase approximation (QRPA) theory. The HFB ground state densities and the QRPA transition densities, respectively, are used in folding calculations for the optical potentials and transition form factors. Spectra and β-decay transitions strengths are reasonably well described. The measured cross section are well reproduced by one-step direct charge exchange distorted wave born approximation (DWBA) calculations. A dominance of unnatural parity transitions is found. This is explained in terms of the spin transfer behaviour of the nucleon–nucleon isovector interaction at low bombarding energy.

Published
2004
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11. Probing the 8He ground state via the 8He(p,t)6He reaction

Author

V. Lapoux, Lydie Giot, F. Auger, D. Beaumel, K. Rusek, N. Alamanos, A. Drouart, E. C. Pollacco, N. Keeley, R. Raabe, F. Skaza, A. Gillibert, Y. Blumenfeld, J. L. Sida, L. Nalpas, P. Roussel-Chomaz, J.A. Scarpaci, R. Wolski, E. Becheva, K. W. Kemper, A. Pakou, S. V. Stepantsov, F. Delaunay, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-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), SPIRAL, 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, Elastic scattering, Nuclear and High Energy Physics, Valence (chemistry), Isotope, 010308 nuclear & particles physics, Direct reactions, 24.50.+g, 21.10.Jx, 24.10.Eq, 8He, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 0103 physical sciences, CRC calculations, Neutron, Halo, Atomic physics, 010306 general physics, Ground state, Wave function, Spectroscopy
Abstract

GANIL E405S; The weakly-bound 8He nucleus exhibits a neutron halo or thick neutron skin and is generally considered to have an α+4n structure in its ground state, with the four valence neutrons each occupying 1p3/2 states outside the α core. The 8He(p,t)6He reaction is a sensitive probe of the ground state structure of 8He, and we present a consistent analysis of new and existing data for this reaction at incident energies of 15.7 and Click to view the MathML source, respectively. Our results are incompatible with the usual assumption of a pure (1p3/2)4 structure and suggest that other configurations such as (1p3/2)2(1p1/2)2 may be present with significant probability in the ground state wave function of 8He.

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