Structure of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">Be</mml:mi><mml:mprescripts/><mml:none/><mml:mn>13</mml:mn></mml:mmultiscripts></mml:math> studied in proton knockout from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="normal">B</mml:mi><mml:mprescripts/><mml:none/><mml:mn>14</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
The neutron-unbound isotope $^{13}\mathrm{Be}$ has been studied in several experiments using different reactions, different projectile energies, and different experimental setups. There is, however, no real consensus in the interpretation of the data, in particular concerning the structure of the low-lying excited states. Gathering new experimental information, which may reveal the $^{13}\mathrm{Be}$ structure, is a challenge, particularly in light of its bridging role between $^{12}\mathrm{Be}$, where the $N=8$ neutron shell breaks down, and the Borromean halo nucleus $^{14}\mathrm{Be}$. The purpose of the present study is to investigate the role of bound excited states in the reaction product $^{12}\mathrm{Be}$ after proton knockout from $^{14}\mathrm{B}$, by measuring coincidences between $^{12}\mathrm{Be}$, neutrons, and $\ensuremath{\gamma}$ rays originating from de-excitation of states fed by neutron decay of $^{13}\mathrm{Be}$. The $^{13}\mathrm{Be}$ isotopes were produced in proton knockout from a 400 MeV/nucleon $^{14}\mathrm{B}$ beam impinging on a ${\mathrm{CH}}_{2}$ target. The $^{12}\mathrm{Be}\text{\ensuremath{-}}n$ relative-energy spectrum $d\ensuremath{\sigma}/d{E}_{fn}$ was obtained from coincidences between $^{12}\mathrm{Be}$(g.s.) and a neutron, and also as threefold coincidences by adding $\ensuremath{\gamma}$ rays, from the de-excitation of excited states in $^{12}\mathrm{Be}$. Neutron decay from the first $5/{2}^{+}$ state in $^{13}\mathrm{Be}$ to the ${2}^{+}$ state in $^{12}\mathrm{Be}$ at 2.11 MeV is confirmed. An energy independence of the proton-knockout mechanism is found from a comparison with data taken with a 35 MeV/nucleon $^{14}\mathrm{B}$ beam. A low-lying $p$-wave resonance in $^{13}\mathrm{Be}(1/{2}^{\ensuremath{-}})$ is confirmed by comparing proton- and neutron-knockout data from $^{14}\mathrm{B}$ and $^{14}\mathrm{Be}$.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.006 |
| Meta-epidemiology (narrow) | 0.004 | 0.006 |
| Meta-epidemiology (broad) | 0.003 | 0.006 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.004 | 0.005 |
| Scholarly communication | 0.003 | 0.005 |
| Open science | 0.007 | 0.005 |
| Research integrity | 0.006 | 0.007 |
| Insufficient payload (model declined to judge) | 0.032 | 0.007 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; both teacher heads agree on what is shown here.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".