Study of the 44Ti(alpha,p)47V reaction and implications for core collapse supernovae
Bibliographic record
Abstract
Space-based γ-ray satellites such as BeppoSAX, COMPTEL and INTEGRAL have reported detection of 44 Ti in the Cassiopeia-A and SN1987a core-collapse supernova remnants.The NuSTAR satellite has recently measured the distribution of 44 Ti γ-ray emission in Cassiopeia-A finding a highly asymmetric distribution.In all cases, the amounts of 44 Ti inferred in the ejecta are higher than expected, even assuming a wide range of progenitor models and masses.The dominant nuclear uncertainty within such models is the rate of the 44 Ti(α, p) 47 V nuclear reaction rate.Through radiochemical separation, a sample of 44 Ti was obtained from highly-irradiated martensitic steel accelerator components of the Paul Scherrer Institute.Transported to CERN, this material was then developed into a beam at the REX-ISOLDE facility and directed onto a gas filled cell.This enabled a study of the 44 Ti(α, p) 47 V reaction at an energy of E cm =4.15 MeV, finding an upper limit for the cross section of 40 µb (68% c.l.).Possible implications for core collapse supernovae are presented.
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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 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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".