{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"d95a8d4fc5a272f939c7519496d8563050dbf03e14fd1785ca47dc243ba62914","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b","df1d5ed9018a2058fa8ad71cab68f9b9f30b31d512782cb46fb0f81c38030fc9"],"salt":"b29cc8ce6637a16d789fbc548aa64edd0733db627c533decf9a040b4e54b7679","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"cosmo.primordial-black-holes.earth-mass-events","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Surveys watching millions of stars see a few brightenings lasting less than a day, caused by passing objects about as heavy as the Earth. They are usually attributed to planets drifting free of any star, but primordial black holes would produce identical events.","posed_since":"2019","precise":"OGLE bulge data contain 6 ultrashort events that Niikura et al. (2019, arXiv:1901.07120) reproduce with Earth-mass PBHs forming about a percent of dark matter, while MOA (Sumi et al. 2023, arXiv:2303.08280) attributes such events to about 21 free-floating planets per star. Determine $f_{\\mathrm{PBH}} = \\Omega_{\\mathrm{PBH}} / \\Omega_{c}$ for $M = 10^{-7}\\ \\text{to}\\ 10^{-5}\\ M_{\\mathrm{sun}}$ ($2 \\times 10^{26}\\ \\text{to}\\ 2 \\times 10^{28}\\ \\mathrm{g}$) by separating lens populations through event-rate dependence on direction (bulge, disk, halo, lines of sight to the LMC and M31) and through lens-distance information.","problem_ref":"df1d5ed9018a2058fa8ad71cab68f9b9f30b31d512782cb46fb0f81c38030fc9","references":"","settled_by":"Nancy Grace Roman Space Telescope microlensing statistics with parallax for short events, compared between the bulge and halo-dominated lines of sight.","status_note":"Mroz et al. (2024, Nature 632, 749) bound $f_{\\mathrm{PBH}} < 0.1$ for $1.3 \\times 10^{-5} \\text{ to } 860\\,M_{\\mathrm{sun}}$ toward the LMC, leaving the Earth-mass range less constrained.","title":"Are ultrashort microlensing events caused by planets or primordial black holes?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"967d72ee5d839cbbfefb08b9e9dc28becd731b21dd7de4d311bb553db5be4779","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"446c261eb16b59cbf174c2376fc611439c05debb8c6f8cdc289f4c95059b9f05","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"A7NtUBW0F1G99Ie_OGSQL-IVR8C6yuuopc6jKHH2_JN0NKzfhrBhDyjHqo39B830CGyIiLnANABkgRbFqgP0Cg"},"schema":"pubphys.envelope/1"},"record_hash":"967d72ee5d839cbbfefb08b9e9dc28becd731b21dd7de4d311bb553db5be4779","leaf_index":3156}