| 1. |
- Grigorenko, L, et al.
(author)
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Scientific program of DERICA-prospective accelerator and storage ring facility for radioactive ion beam research
- 2019
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In: Physics-Uspekhi. - 1468-4780 .- 1063-7869. ; 62:7, s. 675-690
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Journal article (peer-reviewed)abstract
- Studies of radioactive ions (RIs) are the most thriving field of low-energy nuclear physics. In this paper, the concept and the scientific agenda of the prospective accelerator and storage ring facility for RI beam (RIB) research are proposed for a large-scale international project based at the Flerov Laboratory of Nuclear Reactions of the Joint Institute for Nuclear Research. The motivation for the new facility is discussed and its characteristics are briefly presented and shown to be comparable to those of advanced world centers, the so-called "RIB factories". In the project, the emphasis is made on studies with short-lived RIBs in storage rings. A unique feature of the project is the possibility of studying electron-RI interactions in a collider experiment to determine the fundamental properties of nuclear matter, in particular, electromagnetic form factors of exotic nuclei.
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| 2. |
- Marganiec, J., et al.
(author)
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Coulomb breakup of 17Ne from the viewpoint of nuclear astrophysics
- 2012
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In: Proceedings of Science. - Proceedings of Science : Sissa. - 1824-8039.
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Conference paper (peer-reviewed)abstract
- By the Coulomb breakup of 17Ne, the time-reversed reaction 15O(2p,γ)17Ne has been studied. This reaction might play an important role in the rp process, as a break-out reaction of the hot CNO cycle. The secondary 17Ne ion beam with an energy of 500 MeV/nucleon has been dissociated in a Pb target. The reaction products have been detected with the LAND-R3B experimental setup at GSI. The preliminary differential and integral Coulomb dissociation cross section sCoul has been determined, which then will be converted into a photo-absorption cross section sphoto, and a two-proton radiative capture cross section σcap. Additionally, information about the structure of the 17Ne, a potential two-proton halo nucleus, will be received. The analysis is in progress. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence.
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| 3. |
- Muzalevskii, I. A., et al.
(author)
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Resonant states in H 7: Experimental studies of the H 2 (He 8, He 3) reaction
- 2021
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In: Physical Review C. - 2469-9985 .- 2469-9993. ; 103:4
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Journal article (peer-reviewed)abstract
- The extremely neutron-rich system H7 was studied in the direct H2(He8,He3)H7 transfer reaction with a 26 AMeV secondary He8 beam [Bezbakh et al., Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. The missing mass spectrum and center-of-mass angular distributions of H7, as well as the momentum distribution of the H3 fragment in the H7 frame, were constructed. In addition, we carried out another experiment with the same beam but a modified setup, which was cross-checked by the study of the H2(Be10,He3)Li9 reaction. A solid experimental evidence is provided that two resonant states of H7 are located in its spectrum at 2.2(5) and 5.5(3)MeV relative to the H3+4n decay threshold. Also, there are indications that the resonant states at 7.5(3) and 11.0(3)MeV are present in the measured H7 spectrum. Based on the energy and angular distributions, obtained for the studied H2(He8,He3)H7 reaction, the weakly populated 2.2(5)-MeV peak is ascribed to the H7 ground state. It is highly plausible that the firmly ascertained 5.5(3)-MeV state is the 5/2+ member of the H7 excitation 5/2+-3/2+ doublet, built on the 2+ configuration of valence neutrons. The supposed 7.5-MeV state can be another member of this doublet, which could not be resolved in Bezbakh et al. [Phys. Rev. Lett. 124, 022502 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.022502]. Consequently, the two doublet members appeared in the spectrum of H7 in the work mentioned above as a single broad 6.5-MeV peak.
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| 4. |
- Nikolskii, E.Y., et al.
(author)
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H 6 states studied in the H 2 (He 8, He 4) reaction and evidence of an extremely correlated character of the H 5 ground state
- 2022
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In: Physical Review C. - 2469-9993 .- 2469-9985. ; 105:6
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Journal article (peer-reviewed)abstract
- The extremely neutron-rich system H6 was studied in the direct H2(He8,He4)H6 transfer reaction with a 26A MeV secondary He8 beam. The measured missing mass spectrum shows a broad bump at ≈4-8 MeV above the H3+3n decay threshold. This bump can be interpreted as a broad resonant state in H6 at 6.8(5) MeV. The population cross section of such a presumably p-wave state (or it may be few overlapping states) in the energy range from 4 to 8 MeV is dσ/dωc.m.≃190-80+40μb/sr in the angular range 5°<θc.m.<16°. The obtained missing mass spectrum is practically free of H6 events below 3.5 MeV (dσ/dωc.m. 5μb/sr in the same angular range). The steep rise of the H6 missing mass spectrum at ≈3 MeV allows us to derive the lower limit for the possible resonant-state energy in H6 to be 4.5(3) MeV. According to the paring energy estimates, such a 4.5(3) MeV resonance is a realistic candidate for the H6 ground state (g.s.). The obtained results confirm that the decay mechanism of the H7 g.s. (located at 2.2 MeV above the H3+4n threshold) is the "true"(or simultaneous) 4n emission. The resonance energy profiles and the momentum distributions of fragments of the sequential H6→H5(g.s.)+n→H3+3n decay were analyzed by the theoretically updated direct four-body-decay and sequential-emission mechanisms. The measured momentum distributions of the H3 fragments in the H6 rest frame indicate very strong "dineutron-type"correlations in the H5 ground state decay.
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| 5. |
- Marganiec, J, et al.
(author)
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Experimental study of the 15O(2p ,γ)17Ne cross section by Coulomb Dissociation for the rp process
- 2016
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In: Journal of Physics Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596.
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Conference paper (peer-reviewed)abstract
- The time-reversed reaction 15O(2p,γ)17Ne has been studied by the Coulomb dissociation technique. Secondary 17Ne ion beams at 500 AMeV have been produced by fragmentation reactions of 20Ne in a beryllium production target and dissociated on a secondary Pb target. The incoming beam and the reaction products have been identified with the kinematically complete LAND-R3B experimental setup at GSI. The excitation energy prior to decay has been reconstructed by using the invariant-mass method. The preliminary differential and integral Coulomb Dissociation cross sections (σCoul) have been calculated, which provide a photoabsorption (σphoto) and a radiative capture cross section (σcap). Additionally, important information about the nuclear structure of the 17Ne nucleus will be obtained. The analysis is in progress.
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| 6. |
- Markenroth, Karin, 1973, et al.
(author)
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Crossing the dripline to N-11 using elastic resonance scattering
- 2000
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 6203:3
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Journal article (peer-reviewed)abstract
- The level structure of the unbound nucleus N-11 has been studied by C-10+p elastic resonance scattering in inverse geometry with the LISE3 spectrometer at GANIL, using a C-10 beam with an energy of 9.0 MeV/ nucleon. An additional measurement was done at the A1200 spectrometer at MSU. The excitation function above the C-10+p threshold has been determined up to 5 MeV. A potential-model analysis revealed three resonance states at energies 1.27(-0.05)(+0.18) MeV (Gamma = 1.44 +/- 0.2 MeV), 2.01(-0.05)(+0.15) MeV (Gamma = 0.84 +/- 0.2 MeV), and 3.75 +/- 0.05 MeV (Gamma = 0.60 +/- 0.05 MeV) with the spin-parity assignments I-pi=1/2+,1/2,-,5/2+, respectively. Hence, N-11 is shown to have a ground state parity inversion completely analogous to its mirror partner Be-11. A narrow resonance in the excitation function at 4.33 +/- 0.05 MeV was also observed and assigned spin parity 3/2-.
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| 7. |
- Shulgina, N. B., et al.
(author)
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Superhalo of C 22 reexamined
- 2018
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In: Physical Review C. - 2469-9985 .- 2469-9993. ; 97:6
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Journal article (peer-reviewed)abstract
- An unusually large value of the C22 matter radius, extracted by Tanaka et al. [Phys. Rev. Lett. 104, 062701 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.062701] from measured reaction cross sections, attracted great attention of scientific community. Since that time, several experimental works related to the C22 nucleus have appeared in the literature. Some of the experimental data, measured with high accuracy, allow us to fix C22 structure more reliably. Two limiting models reproducing C22 nuclear structure within the three-body cluster approach, that allow us to describe all existing experimental data, are presented. The C22 ground state, continuum structure, and geometry are obtained. With fixed C22 wave function, the prediction for the soft dipole mode in C22, which is studied in the process of Coulomb fragmentation, is performed.
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| 8. |
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| 9. |
- Grigorenko, L, et al.
(author)
-
Asymptotic normalization coefficient method for two-proton radiative capture
- 2020
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 811
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Journal article (peer-reviewed)abstract
- The method of asymptotic normalization coefficients is a standard approach for studies of two-body non-resonant radiative capture processes in nuclear astrophysics. This method suggests a fully analytical description of the radiative capture cross section in the low-energy region of the astrophysical interest. We demonstrate how this method can be generalized to the case of three-body 2p radiative captures. It was found that an essential feature of this process is the highly correlated nature of the capture. This reflects the complexity of three-body Coulomb continuum problem. Radiative capture 15O+p+p→17Ne+γ is considered as an illustration.
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| 10. |
- Grigorenko, L, et al.
(author)
-
High-precision studies of the soft dipole mode in two-neutron halo nuclei: The He 6 case
- 2020
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 102:1
-
Journal article (peer-reviewed)abstract
- The soft dipole E1 strength function is calculated for the transition from the He60+ ground state to the 1- continuum He4+n+n. The calculations were performed within the hyperspherical harmonics formalism. The sensitivity of the results to the He6 ground-state structure and to final-state interactions, are analyzed. The large-basis calculations show the reliably converged results for soft dipole strength function and for momentum correlations of the He6→He4+n+n dissociation products. Transition mechanisms are analyzed based on the momentum correlations. The comparison with experimental data is provided.
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| 11. |
- Grigorenko, L, et al.
(author)
-
Three-body vs. dineutron approach to two-neutron radiative capture in 6 He
- 2020
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 807
-
Journal article (peer-reviewed)abstract
- The low-energy behavior of the strength function for the 1− soft dipole excitation in 6He is studied theoretically. Use of very large basis sizes and well-grounded extrapolation procedures allows to move to energies as small as 1 keV, at which the low-energy asymptotic behavior of the E1 strength function seems to be achieved. It is found that the low-energy behavior of the strength function is well described in the effective three-body “dynamical dineutron model”. The astrophysical rate for the α+n+n→6He+γ is calculated. Comparison with the previous calculations is performed.
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| 12. |
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| 13. |
- Parfenova, Y. L., et al.
(author)
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CNO cycle: "soft E1" mode of the Ne-17 excitation in the Ne-17+gamma -> O-15+2p reaction
- 2016
-
In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 665:1
-
Conference paper (peer-reviewed)abstract
- The O-15(2p, gamma) Ne-17 reaction is studied using the time-reversed reaction of the Ne-17 E1 Coulomb dissociation on lead target in the context of nuclear astrophysics. Looking for the relation between the data on the Coulomb excitation and the astrophysical 2p-capture rate, one faces problem to extract the Coulomb E1 strength function from the measured Coulex cross section. We use a number of phenomenological approaches to estimate influence of such processes as Coulomb-nuclear interference, populations of states with different J(pi), etc. We calculate the Ne-17+ 2p astrophysical capture rate and compare the results with different calculations.
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| 14. |
- Parfenova, Yu L., et al.
(author)
-
From Coulomb excitation cross sections to nonresonant astrophysical rates in three-body systems: The Ne-17 case
- 2018
-
In: Physical Review C. - 2469-9985 .- 2469-9993. ; 98:3
-
Journal article (peer-reviewed)abstract
- Coulomb and nuclear dissociation of Ne-17 on light and heavy targets are studied theoretically. The dipole E1 strength function is determined in a broad energy range including energies of astrophysical interest. Dependence of the strength function on different parameters of the Ne-17 ground-state structure and continuum dynamics is analyzed in a three-body model. The discovered dependence plays an important role for studies of the strength functions for the three-body E1 dissociation and radiative capture. The constraints on the [s(2)]/[d(2)] configuration mixing in Ne-17 and on p-wave interaction in the O-15+p channel are imposed based on experimental data for Ne-17 Coulomb dissociation on heavy target.
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| 15. |
- Shulgina, N. B., et al.
(author)
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11 Li structure from experimental data
- 2009
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 825:3-4, s. 175-199
-
Journal article (peer-reviewed)abstract
- An analytical wave function for the 11Li ground state is constructed in a three-body 9Li + n + n approach. Its parameters are fixed from the fit to the set of most accurate experimental data and tested on all other available data. The obtained 11Li ground state wave function allows to describe all considered experimental data within their error bars simultaneously. The main contributions to the 11Li ground state wave function are found to come from (s1 / 2)2 (37%) and (p1 / 2)2 (47%) components.
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