<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mn>2</mml:mn><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:math> to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mn>3</mml:mn><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup><mml:mo> </mml:mo><mml:mi>γ</mml:mi></mml:math> width in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Na</mml:mi><mml:mprescripts/><mml:none/><mml:mn>22</mml:mn></mml:mmultiscripts></mml:math> and second class currents
Bibliographic record
Abstract
Background: A previous measurement of the $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ directional coefficient in $^{22}\mathrm{Na}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$ decay was used to extract recoil-order form factors. The data indicate the requirement of a significant induced-tensor matrix element for the decay. This conclusion largely relies on a standard-model-allowed weak magnetism form factor which was determined using an unpublished value of the analog ${2}_{1}^{+}\ensuremath{\rightarrow}{3}_{1}^{+}$ $\ensuremath{\gamma}$ branch in $^{22}\mathrm{Na}$, with the further assumption that the transition is dominated by its isovector $M1$ component.Purpose: Our aim is to determine the ${2}_{1}^{+}\ensuremath{\rightarrow}{3}_{1}^{+}$ width in $^{22}\mathrm{Na}$ in order to obtain an independent measurement of the weak magnetism form factor for the $\ensuremath{\beta}$ decay.Methods: A $^{21}\mathrm{Ne}(p,\ensuremath{\gamma})$ resonance reaction on an implanted target was used to produce the first ${2}^{+}$ state in $^{22}\mathrm{Na}$ at ${E}_{x}=1952$ keV. Deexcitation $\ensuremath{\gamma}$ rays were registered with two 100% relative efficiency high purity germanium detectors.Results: We obtain for the first time an unambiguous determination of the ${2}_{1}^{+}\ensuremath{\rightarrow}{3}_{1}^{+}$ branch in $^{22}\mathrm{Na}$ to be $0.45(8)%$.Conclusions: Using the conserved vector current (CVC) hypothesis, our branch determines the weak magnetism form factor for $^{22}\mathrm{Na}\phantom{\rule{4pt}{0ex}}\ensuremath{\beta}$ decay to be $|b/A{c}_{1}|=8.9(1.2)$. Together with the $\ensuremath{\beta}\text{\ensuremath{-}}\ensuremath{\gamma}$ angular correlation coefficient, we obtain a large induced-tensor form factor for the decay that continues to disagree with theoretical predictions. Two plausible explanations are suggested.
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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 | 0.003 | 0.010 |
| Meta-epidemiology (narrow) | 0.004 | 0.003 |
| Meta-epidemiology (broad) | 0.002 | 0.003 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.012 | 0.011 |
| Open science | 0.005 | 0.005 |
| Research integrity | 0.004 | 0.005 |
| Insufficient payload (model declined to judge) | 0.535 | 0.728 |
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".