Light Particle Solution to the Cosmic Lithium Problem
Bibliographic record
Abstract
We point out that the cosmological abundance of ^{7}Li can be reduced down to observed values if during its formation, big bang nucleosynthesis is modified by the presence of light electrically neutral particles X that have substantial interactions with nucleons. We find that the lithium problem can be solved without affecting the precisely measured abundances of deuterium and helium if the following conditions are satisfied: the mass (energy) and lifetimes of such particles are bounded by 1.6 MeV≤m_{X}(E_{X})≤20 MeV and few100s≲τ_{X}≲10^{4} s, and the abundance times the absorption cross section by either deuterium or ^{7}Be are comparable to the Hubble rate, n_{X}σ_{abs}v∼H, at the time of ^{7}Be formation. We include X-initiated reactions into the primordial nucleosynthesis framework, observe that it leads to a substantial reduction of the freeze-out abundances of ^{7}Li+^{7}Be, and find specific model realizations of this scenario. Concentrating on the axionlike-particle case, X=a, we show that all these conditions can be satisfied if the coupling to d quarks is in the range of f_{d}^{-1}∼TeV^{-1}, which can be probed at intensity frontier experiments.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".