High-precision half-life determination for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi mathvariant="bold">Na</mml:mi><mml:mprescripts/><mml:none/><mml:mn>21</mml:mn></mml:mmultiscripts></mml:math> using a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>4</mml:mn><mml:mi>π</mml:mi></mml:mrow></mml:math> gas-proportional counter
Bibliographic record
Abstract
A high-precision half-life measurement for the superallowed ${\ensuremath{\beta}}^{+}$ transition between the isospin $T=1/2$ mirror nuclei $^{21}\mathrm{Na}$ and $^{21}\mathrm{Ne}$ has been performed at the TRIUMF-ISAC radioactive ion beam facility yielding ${T}_{1/2}=22.4506(33)$ s, a result that is a factor of 4 more precise than the previous world-average half-life for $^{21}\mathrm{Na}$ and represents the single most precisely determined half-life for a transition between mirror nuclei to date. The contribution to the uncertainty in the $^{21}\mathrm{Na} \mathcal{F}{t}^{\mathrm{mirror}}$ value due to the half-life is now reduced to the level of the nuclear-structure-dependent theoretical corrections, leaving the branching ratio as the dominant experimental uncertainty.
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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 | 0.004 | 0.003 |
| Meta-epidemiology (narrow) | 0.002 | 0.003 |
| Meta-epidemiology (broad) | 0.001 | 0.004 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.005 | 0.003 |
| Scholarly communication | 0.004 | 0.004 |
| Open science | 0.004 | 0.005 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.020 | 0.006 |
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".