Spectroscopy of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Be</mml:mi><mml:mprescripts/><mml:none/><mml:mn>13</mml:mn></mml:mmultiscripts></mml:math> through isobaric analog states in <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>13</mml:mn></mml:mmultiscripts></mml:math>
Bibliographic record
Abstract
Background: Spectroscopy of the exotic, neutron unbound beryllium isotope $^{13}\mathrm{Be}$ is still a puzzle despite significant experimental efforts.Purpose: We aim to observe $T=5/2$ states in $^{13}\mathrm{B}$, establish spin-parities and spectroscopic factors, and use isospin symmetry to inform spectroscopy of $^{13}\mathrm{Be}$.Methods: Excitation functions for resonance elastic scattering of $^{12}\mathrm{Be}$ on protons were measured in the center-of-mass energy range from 1 to 5 MeV.Results: Two $T=5/2$ states in $^{13}\mathrm{B}$ at excitation energies 18.25 and 19.95 MeV were observed. Unambiguous $1/{2}^{+}$ and $5/{2}^{+}$ spin-parity assignments were made, and spectroscopic factors were established using the $R$-matrix analysis of the measured $^{12}\mathrm{Be}+p$ excitation functions.Conclusions: We provide the first direct and unambiguous spin-parity assignments and spectroscopic factor measurements for the resonances in the $A=13, T=5/2$ isobaric multiplet. This puts us on a solid footing to identify the 2.3 MeV state in $^{13}\mathrm{Be}$ as $5/{2}^{+}$ and infer the existence of an $s$-wave ($1/{2}^{+}$) resonance at around 0.6 MeV with relatively small spectroscopic factor.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.004 | 0.006 |
| Meta-epidemiology (broad) | 0.003 | 0.006 |
| Bibliometrics | 0.001 | 0.005 |
| Science and technology studies | 0.005 | 0.005 |
| Scholarly communication | 0.004 | 0.005 |
| Open science | 0.007 | 0.009 |
| Research integrity | 0.003 | 0.007 |
| Insufficient payload (model declined to judge) | 0.015 | 0.011 |
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".