{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"22a4fda67095ed20231f222ef7f5aa19c113bd6cbbc86bf0763beef7a6b8383a","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","ed5e485b3467dc65495dddf71ecabf6c985963ff241c7c94e99b47c98c1ea091"],"salt":"3f22f8d6a887c5385fae69b697ff4abcb5b43bae297373b5f0174d903e7d4460","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"cosmo.lithium-problem.lithium7-deficit","kind":"phenomenon","literature_status":"open","n":"2","parents":[],"plain":"Old metal-poor stars in the Milky Way halo show a constant lithium level, but it is about three times below the Big Bang prediction. Either the stars destroyed lithium, or the early universe made less of it.","posed_since":"","precise":"Standard BBN with the Planck baryon density $\\eta \\sim 6.1 \\times 10^{-10}$ predicts $\\mathrm{Li}/\\mathrm{H} \\sim 5 \\times 10^{-10}$, while the Spite plateau of metal-poor dwarfs ($[\\mathrm{Fe}/\\mathrm{H}] < -1.5$) gives $\\mathrm{Li}/\\mathrm{H} \\sim 1.6 \\times 10^{-10}$, a factor 3 to 4 at more than $5\\,\\sigma$. Identify the cause: stellar depletion by atomic diffusion and mixing, nuclear-rate errors, or non-standard physics (decaying particles, varying constants).","problem_ref":"ed5e485b3467dc65495dddf71ecabf6c985963ff241c7c94e99b47c98c1ea091","references":"","settled_by":"A measurement of unprocessed lithium, or a validated stellar model reproducing the plateau from the BBN value.","status_note":"2024 to 2025 work favors stellar depletion and finds nuclear-rate solutions negligible, but no quantitative stellar model is established.","title":"What explains the threefold lithium-7 deficit in old halo stars?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f90df53eb0c2d81b277baddc672c4c8ba43dbf78ad4b29cadd0f4046da930d22","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ec4453c1131ec651997be42d49fe6feb4605a4dd693046ec8f03962d2fdd1173","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"IxWAZp2ArHJmPN6moCUxqeAWjJumPZFoXEwtMl_qOG5VwQP3v1wRpgOfMAqBUAElHhxQbaLgxdJz0Rn5mGZ2Cw"},"schema":"pubphys.envelope/1"},"record_hash":"f90df53eb0c2d81b277baddc672c4c8ba43dbf78ad4b29cadd0f4046da930d22","leaf_index":3150}