Search for highly excited states in light nuclei with three-body reactions

Franke, R.; Kochskämper, K.; Steinheuer, B.; Wingender, K.; Witsch, W. von; Machner, H.

doi:10.1016/0375-9474(85)90270-2

Cited by 35 publications

(10 citation statements)

References 23 publications

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“…high bombarding energies, forward angles), it may be reasonable to assume that either case a or b is applicable. The formula (11) of case a has been used previously in many papers with reference to the ground state of 5He or 5Li, but always with a ::::; 3 fm (in particular see Hamburger and Cameron 1960;Ohlsen and Young 1964;Franke et al 1985), Comparison of the calculated and experimental values in Table 2 does not enable one to select a best value of the channel radius; for some properties the calculated values are insensitive to the value of a, other properties favour a large value of a and still others a small value, while there appears to be a clear discrepancy for the energy of the 4--excited state in 5Li. The large width of the 4--state, however, makes measurements of its properties very difficult.…”

Section: R-matrix Fits To Scattering and Reaction Datamentioning

confidence: 99%

States of 5He and 5Li

Barker¹,

Woods²

1985

Aust. J. Phys.

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A recent shell model calculation has predicted a low-lying! + level in 5He, in apparent conflict with experimental results. We have confirmed the prediction with an alternative shell model interaction chosen specifically to fit properties of light nuclei. The level is expected to be very broad so that it would not be easily seen in reactions. It should contribute significantly to n-a phase shifts, but did not appear in previous analyses because of the small value of about 3 fm chosen for the channel radius a. A ! + level at the expected energy of about 7 MeV is obtained for a ::::: 5·1 fm. Broad ~ + and ~ + levels are then found at about 14 MeV in agreement with the shell model calculations. Properties of the low-lying ~ -and! -levels in 5He and 5Li are discussed, but the measured values now available do not favour a particular value of the channel radius.

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Section: R-matrix Fits To Scattering and Reaction Datamentioning

confidence: 99%

States of 5He and 5Li

Barker¹,

Woods²

1985

Aust. J. Phys.

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“…We have checked that, for a given interaction, the g.s. energies of the well- [3][4][5][6][7], [11][12][13][14][15][16][17] and [17,18], respectively. The FY calculations [29] with N 3 LO, INOY and MT13 interactions are shown (right) for comparison.…”

Section: Resultsmentioning

confidence: 99%

“…Four-nucleon (4N ) systems are the lightest nuclear systems to exhibit resonances at low energies [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. With the highest isospin quantum number of |T z | = T = 2, the possible tetraneutron resonance has attracted considerable attention due to its pure neutron character.…”

Section: Introductionmentioning

confidence: 99%

“…By reducing the isospin quantum number, 4 H, 4 He and 4 Li form a unique T = 1 isospin triplet of 4N resonances with many experimental data available . However, the data providing the energies and widths of the A = 4 resonances are neither conclusive nor even consistent with each other [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. In the experiments where the missing mass method is used, the resonance positions in energy distributions depend on the resonance parameters [22].…”

Section: Introductionmentioning

confidence: 99%

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Resonances of $A=4$ $T=1$ isospin triplet states within the \textit{ab initio} no-core Gamow shell model

Li,

Michel,

Zuo

et al. 2021

Preprint

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The A = 4 nuclei, i.e., 4 H, 4 He and 4 Li, establish an interesting isospin T = 1 isobaric system. 4 H and 4 Li are unbound broad resonances, whereas 4 He is deeply bound in its ground state but unbound in all its excited states. The present situation is that experiments so far have not given consistent data on the resonances. Few-body calculations have well studied the scatterings of the 4N systems. In the present work, we provide many-body calculations of the broad resonance structures, in an ab initio framework with modern realistic interactions. It occurs that, indeed, 4 H, 4 Li and excited 4 He are broad resonances, which is in accordance with experimental observations. The calculations also show that the first 1 − excited state almost degenerates with the 2 − ground state in the pair of mirror isobars of 4 H and 4 Li, which may suggest that the experimental data on energy and width are the mixture of the ground state and the first excited state. The T = 1 isospin triplet formed with an excited state of 4 He and ground states of 4 H and 4 Li is studied, focusing on the effect of isospin symmetry breaking.

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“…This is particularly feasible for light nuclei, where the binding limits and large neutron-to-proton ratios can be reached by adding few nucleons to stable isotopes. In hydrogen, experiments have already obtained evidences of 4,5,6,7 H isotopes, a chain of four resonances beyond the neutron dripline [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]. These systems are found to decay by neutron emission and thus believed to be built on a core of 3 H surrounded by neutrons confined by a centrifugal barrier and grouped in pairs.…”

Section: Introductionmentioning

confidence: 99%

Ground-state properties of super-heavy hydrogen-7

Caamaño

Roger

Moro

et al. 2020

Preprint

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The properties of nuclei with extreme neutron–to–proton ratios, far from those naturally occurring on Earth, are key to understand nuclear forces and how nucleons hold together to form nuclei. 7H, with six neutrons and a single proton, is the nuclear system with the most unbalanced neutron–to–proton ratio known so far. However, its sheer existence and properties are still a challenge for experimental efforts and theoretical models. Here we report the formation of 7H as a resonance, detected with independent observables, and the first measurement of the structure and basic characteristics of its ground state. It is found that 7H is arranged as a 3H core surrounded by an extended four-neutron halo, with a unique four-neutron decay and a relatively long half-life thanks to neutron pairing. These properties are a prime example of new phenomena occurring in the most pure-neutron nuclear matter we can access in the laboratory.

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Search for highly excited states in light nuclei with three-body reactions

Cited by 35 publications

References 23 publications

States of 5He and 5Li

States of 5He and 5Li

Resonances of $A=4$ $T=1$ isospin triplet states within the \textit{ab initio} no-core Gamow shell model

Ground-state properties of super-heavy hydrogen-7

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