Modified big bang nucleosynthesis with nonstandard neutron sources
Bibliographic record
Abstract
During big bang nucleosynthesis, any injection of extra neutrons around the time of the $^{7}\mathrm{Be}$ formation, i.e. at a temperature of order $T\ensuremath{\simeq}50\text{ }\mathrm{keV}$, can reduce the predicted freeze-out amount of $^{7}\mathrm{Be}+^{7}\mathrm{Li}$ that otherwise remains in sharp contradiction with the Spite plateau value inferred from the observations of Pop II stars. However, the growing confidence in the primordial $\mathrm{D}/\mathrm{H}$ determinations puts a strong constraint on any such scenario. We address this issue in detail, analyzing different temporal patterns of neutron injection, such as decay, annihilation, resonant annihilation, and oscillation between mirror and standard model world neutrons. For this latter case, we derive the realistic injection pattern taking into account thermal effects (damping and refraction) in the primordial plasma. If the extra-neutron supply is the sole nonstandard mechanism operating during the big bang nucleosynthesis, the suppression of lithium abundance below $\mathrm{Li}/\mathrm{H}\ensuremath{\le}1.9\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}10}$ always leads to the overproduction of deuterium, $\mathrm{D}/\mathrm{H}\ensuremath{\ge}3.6\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}5}$, well outside the error bars suggested by recent observations.
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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 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".