Bibliographic record
Abstract
We consider primordial nucleosynthesis in the presence of hypothetical quasi-stable doubly charged particles. Existence of $X^{--}$ with macroscopic lifetimes will lead to the formation of its bound states with $^4$He and other light elements, significantly facilitating the subsequent formation of lithium nuclei. From observational constraints on maximum allowable amount of lithium, that we update in this work, we derive strong constraints on the abundance and lifetime of $X^{--}$. In a likely cosmological freeze-out scenario with temperatures initially exceeding the mass of $X^{--}$, the BBN constrains the lifetime of these particles to be less than about 100 seconds. For parametrically long lifetimes, lithium abundance data constrain $X^{--}$ abundance to be less than $10^{-9}$ relative to protons, regardless of whether these particles decay or remain stable. Stable particles could saturate the dark matter density only if their mass is comparable to or in excess of $10^{10}$ GeV, and most of $X^{--}$ will be found in bound states with beryllium nuclei, so that chemically they would appear as abnormally heavy helium isotopes.
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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 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.007 | 0.002 |
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".