Discovery of isotopes with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" display="inline" overflow="scroll"><mml:mi>Z</mml:mi><mml:mo>≤</mml:mo><mml:mn>10</mml:mn></mml:math>

Thoennessen, M.

doi:10.1016/j.adt.2011.08.002

Cited by 24 publications

(9 citation statements)

References 224 publications

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“…Arai and coworkers [5], using a microscopic multicluster model predicted the '/2+ at around 1.2 MeV, with a large width of about 3 MeV. It is apparent that the variation in calculations matches that of the measurements, from which, since the discovery of 9B in 1940 [6,7], the >/2+ excited state has been reported somewhere between 0.8 and 1.8 MeV [1,8,9].…”

Section: Introductionmentioning

confidence: 79%

Spectroscopy ofB9via high-resolution ejectile-tagged recoil break-up

et al. 2015

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An experiment has been carried out using the 9Be(3He, r)9B* reaction at a beam energy of 33 MeV. A large acceptance silicon-strip array was used to detect the 9B* break-up in coincidence with the triton ejectiles in the high-resolution Munich-Q3D spectrograph. The excitation energy regime <3 MeV has been explored and the spectrum resulting from proton decaying states, isolated and characterized. Additional resonance strength is observed at 1.86 MeV ±70 keV(stat) ±35 keV(syst), in agreement with two other recent measurements at higher energies and different angles. The consequences for the "missing" >/2+ first excited state are discussed. Additionally, the branching ratios for the 2.36 MeV 5/i~ state have been measured as r»o/r = 0.98 ± 0.12 and i> /r = 0.016 ± 0.008, in close agreement with earlier work.

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Section: Introductionmentioning

confidence: 79%

Spectroscopy ofB9via high-resolution ejectile-tagged recoil break-up

et al. 2015

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“…As shown in the level scheme of Figure 5.3 and discussed in 2.2, a low lying triplet of states is expected, and within the uncertainties of these calculations it is possible that they be neutron unbound. Given the agreement between [12,16] regarding the placement and assignment of the 3/2 + and the determination of the ground state to be spin and parity 1/2 + [60], the best explanation for a near-threshold resonance would be the 5/2 + 1 at 383±15 keV (shown as the dashed line in Figure 5.3). This immediately begs two questions.…”

Section: Experimental Setup and Data Analysismentioning

confidence: 99%

“…The evolution of these gaps towards lighter-Z nuclei is less clear and decay properties of neutron-unbound states have only been measured in 17 C and 19 C [10]. 19 C was first observed in 1974 by Bowman et al [11,12] and it is the first bound nuclide in the A = 3Z +1 sequence. All lighter nuclides within this series, 4 H, 7 He, 10 Li, 13 Be, and 16 B are unbound.…”

Section: Introductionmentioning

confidence: 99%

Observation of a low-lying neutron-unbound state in 19C

et al. 2013

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Proton removal reactions from a secondary 22 N beam were utilized to populate unbound states in neutronrich carbon isotopes. Neutrons were measured with the Modular Neutron Array (MoNA) in coincidence with carbon fragments. A resonance with a decay energy of 76 (14) keV was observed in the system 18 C +n corresponding to a state in 19 C at an excitation energy of 653 (95) keV. This resonance could correspond to the first 5/2 + state which was recently speculated to be unbound in order to describe 1n and 2n removal cross section measurements from 20 C.

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“…The majority of the current nuclear structure models predict 26 O to be bound [8][9][10][11][12][13]. Experimentally it has been shown that 24 O is bound [14] while repeated searches for bound 25 O and 26 O have been unsuccessful [15][16][17][18][19][20][21], although 25 O had initially been reported as being particle stable [22]. Shellmodel calculations using phenomenological interactions do predict 26 O to be unbound: SDPF-M [23] by 77 keV and USD05a [24] by 510 keV.…”

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confidence: 99%

Evidence for the Ground-State Resonance ofO26

et al. 2012

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Evidence for the ground state of the neutron-unbound nucleus 26 O was observed for the first time in the single proton-knockout reaction from a 82 MeV/u 27 F beam. Neutrons were measured in coincidence with 24 O fragments. 26 O was determined to be unbound by 150 +50 −150 keV from the observation of low-energy neutrons. This result agrees with recent shell model calculations based on microscopic two-and three-nucleon forces.A major challenge in nuclear physics remains the description of nuclei based on fundamental interactions. "Ab-initio" approaches have been developed to calculate nuclear properties based on nucleon-nucleon scattering data up to A ∼ 12 [1]. Recent advances in nuclear theory made it possible to describe some fundamental properties of light nuclei up to oxygen based on two-and three-nucleon interactions [2][3][4][5][6]. On the way to heavier nuclides it will be critical for these models to describe the dramatic change in the location of the neutron dripline from oxygen (N = 16) to fluorine (N ≥ 22) which was first pointed out by Sakurai et al. [7]. The addition of one proton binds at least six additional neutrons. The two-neutron separation energy of 26 O serves as an important benchmark for these calculations. The majority of the current nuclear structure models predict 26 O to be bound [8][9][10][11][12][13] respect to two-neutron emission. 26 O is thus also an excellent candidate for di-neutron emission. Furthermore calculations by Grigorenko et al. predict that the emission of a pair of correlated neutrons might be hindered so that for very low decay energies lifetimes on the order of pico-to nanoseconds could be possible [27].We searched for unbound states in 26 O using oneproton knockout reactions from 27 F and by measuring neutrons in coincidence with 24 O fragments. Figure 1 shows a schematic level scheme of the possible decay paths for predicted states of 26 O. In this letter we present the first evidence for the observation of the unbound ground state of 26 O.

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Discovery of isotopes with Z≤10

Cited by 24 publications

References 224 publications

Spectroscopy ofB9via high-resolution ejectile-tagged recoil break-up

Spectroscopy ofB9via high-resolution ejectile-tagged recoil break-up

Observation of a low-lying neutron-unbound state in 19C

Evidence for the Ground-State Resonance ofO26

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