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 machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.050 | 0.018 |
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; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".