Direct Measurement of the Astrophysical<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">K</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>38</mml:mn></mml:mrow></mml:mmultiscripts><mml:mo stretchy="false">(</mml:mo><mml:mi>p</mml:mi><mml:mo>,</mml:mo><mml:mi>γ</mml:mi><mml:mo stretchy="false">)</mml:mo><mml:mmultiscripts><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>39</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>Reaction and Its Influence on the Production of Nuclides toward the End Point of Nova Nucleosynthesis
Bibliographic record
Abstract
We have performed the first direct measurement of the $^{38}\mathrm{K}(p,\ensuremath{\gamma})^{39}\mathrm{Ca}$ reaction using a beam of radioactive $^{38}\mathrm{K}$. A proposed $\ensuremath{\ell}=0$ resonance in the $^{38}\mathrm{K}+p$ system has been identified at 679(2) keV with an associated strength of ${120}_{\ensuremath{-}30}^{+50}\text{ }\text{ }\mathrm{meV}$. Upper limits of 1.16 (3.5) and 8.6 (26) meV at the 68% (95%) confidence level were also established for two further expected $\ensuremath{\ell}=0$ resonances at 386 and 515 keV, respectively. The present results have reduced uncertainties in the $^{38}\mathrm{K}(p,\ensuremath{\gamma})^{39}\mathrm{Ca}$ reaction rate at temperatures of 0.4 GK by more than 2 orders of magnitude and indicate that Ar and Ca may be ejected in observable quantities by oxygen-neon novae. However, based on the newly evaluated rate, the $^{38}\mathrm{K}(p,\ensuremath{\gamma})^{39}\mathrm{Ca}$ path is unlikely to be responsible for the production of Ar and Ca in significantly enhanced quantities relative to solar abundances.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.076 | 0.064 |
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".