Elucidation of the Anomalous<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>A</mml:mi><mml:mo>=</mml:mo><mml:mn>9</mml:mn></mml:math>Isospin Quartet Behavior
Bibliographic record
Abstract
Recent high-precision mass measurements of $^{9}\mathrm{Li}$ and $^{9}\mathrm{Be}$, performed with the TITAN Penning trap at the TRIUMF ISAC facility, are analyzed in light of state-of-the-art shell model calculations. We find an explanation for the anomalous isobaric mass multiplet equation behavior for the two $A=9$ quartets. The presence of a cubic $d=6.3(17)\text{ }\text{ }\mathrm{keV}$ term for the ${J}^{\ensuremath{\pi}}=3/{2}^{\ensuremath{-}}$ quartet and the vanishing cubic term for the excited ${J}^{\ensuremath{\pi}}=1/{2}^{\ensuremath{-}}$ multiplet depend upon the presence of a nearby $T=1/2$ state in $^{9}\mathrm{B}$ and $^{9}\mathrm{Be}$ that induces isospin mixing. This is contrary to previous hypotheses involving purely Coulomb and charge-dependent effects. $T=1/2$ states have been observed near the calculated energy, above the $T=3/2$ state. However, an experimental confirmation of their ${J}^{\ensuremath{\pi}}$ is needed.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.001 |
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".