<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>-wave scattering lengths for the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mmultiscripts><mml:mi>Be</mml:mi><mml:mprescripts/><mml:none/><mml:mn>7</mml:mn></mml:mmultiscripts><mml:mo>+</mml:mo><mml:mi>p</mml:mi></mml:mrow></mml:math> system from an <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>R</mml:mi></mml:mrow></mml:math>-matrix analysis
Bibliographic record
Abstract
The astrophysical $S$ factor for the radiative proton capture reaction on $^{7}\mathrm{Be}$ (${S}_{17}$) at low energies is affected by the $s$-wave scattering lengths. We report the measurement of elastic and inelastic scattering cross sections for the $^{7}\mathrm{Be}+p$ system in the center-of-mass energy range 0.474--2.740 MeV and center-of-mass angular range ${70}^{\ensuremath{\circ}}$--${150}^{\ensuremath{\circ}}$. A radioactive $^{7}\mathrm{Be}$ beam produced at Oak Ridge National Laboratory's (ORNL) Holifield Radioactive Ion Beam Facility was accelerated and bombarded a thin polypropylene ${({\mathrm{CH}}_{2})}_{n}$ target. Scattered ions were detected in the segmented Silicon Detector Array. Using an $R$-matrix analysis of ORNL and Louvain-la-Neuve cross-section data, the $s$-wave scattering lengths for channel spins 1 and 2 were determined to be $17.{34}_{\ensuremath{-}1.33}^{+1.11}$ and $\ensuremath{-}3.{18}_{\ensuremath{-}0.50}^{+0.55}$ fm, respectively. The uncertainty in the $s$-wave scattering lengths reported in this work is smaller by a factor of 5--8 compared to the previous measurement, which may reduce the overall uncertainty in ${S}_{17}$ at zero energy. The level structure of $^{8}\mathrm{B}$ is discussed based upon the results from this work. Evidence for the existence of ${0}^{+}$ and ${2}^{+}$ levels in $^{8}\mathrm{B}$ at 1.9 and 2.21 MeV, respectively, is observed.
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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 | 0.002 | 0.005 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.001 | 0.003 |
| Bibliometrics | 0.003 | 0.004 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.006 | 0.005 |
| Open science | 0.004 | 0.003 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.401 | 0.369 |
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".