{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8f7792b3010544b07076a9ea7d10202fc5908ccbecae4c222f2e46696ab51bf3","created":"2026-10-03T07:17:55Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"84e23c7edf14c2e4ffe7453d787f06db144f357411432a8a7a73debcb4db796b","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"astro.high-energy-neutrino-sources.km3-event","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"In 2023 a detector in the Mediterranean recorded a neutrino about 30 times more energetic than any seen before, while the larger IceCube detector has seen none like it.","posed_since":"2025","precise":"KM3-230213A (reconstructed neutrino energy $\\sim 220\\,\\mathrm{PeV}$, 72 PeV to 2.6 EeV at 90 percent confidence) implies, if steady and isotropic, a flux in tension at about 2.5 to 3 $\\sigma$ with IceCube non-detections above 10 PeV. Determine whether it is a cosmogenic neutrino, emission from a transient point source such as a flaring blazar in the error region, or an upward fluctuation, and which flux is consistent with both detectors. Answer: a joint flux estimate and a source attribution with probabilities.","problem_ref":null,"references":"","settled_by":"Joint IceCube-KM3NeT analysis with added exposure, and detection or exclusion of further events above $1e17\\,\\mathrm{eV}$.","status_note":"2025: KM3NeT published the event; follow-up analyses found that a steady cosmogenic origin requires a flux in tension with IceCube limits, leaving transient and fluctuation explanations.","title":"Origin of the $220\\,\\mathrm{PeV}$ neutrino event KM3-230213A","topic_ref":"05faf7b2786da464712d8108b8ce0e3e18f89534b1760bb4d3030768e35f2a73"},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f149efadf15a91ad6b3b2192a848c16a13bf4958d536c71b1c88543c694986db","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"4023169db35214e901f8f4aba19884cd5bc882a340def6faf1f24af79ac97277","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"T0co5MB_kxhgxiH_e5gWLp37G15D-SKB_5LVwOhIsGnMQg8rLvlCOVnM3zG31xXcl2V_IeCYGlzV1IbqGN-FDA"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIQCMWnbNSFOkB-PSroZiEzVvIgqNA3vb68fJK95rJcnfxIEAhX57Wy0XsWsH1Nv-1L_jz-8AQHxFKqbVDTDm4DRxrCPAgWCOVckHCKfAKoTlpNwXWUlKRqW9HJ_0PrIUaKJ5CZucI8CDPKDB9sztSf5Ug5iGW2_hmskBlAF4iPUoC0Iq0t9OzQAjxIHWLP-b2jvFJxB9yOgo3Ax1ULcTisr9VfiCowrCfvAysCPAgIpNRxpRR8OI5lwrh4iK8fcMNsJs5yW_DDAUqbwmG2C4I8SCS4I2QHtAryJA81fZfCLw64U-vtMOtxGAXkrMhnGO_1AjwIE6KAygcVZPIUTkvRQL_cxDpqVObTFmOXRCZmyxKzTVeCPAgDwiS_6mbTnnYK_oMGqQLov2YRVYIj9Er1NWLuDHHhV8I8CDcBxRb7fDApTWNNvjZ_r2lDpQT60DYte3pStKjciGgOAjwIK9SXvHBwgJE5CknXtp2lOqKcbHlJ-ncP9sNjnTHUJsmCPEgytIBB3x7TFDT-XqOV-9vpqw1NKoAu0dhtsCbAMql2L0I8CCtNZgmApuKULvPC9nsMCaM05arV-F3o5FTlnJCnRvdMgjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3WablSaV64Wfn7Pmby5WLyI-A0I8QRqwKw78AhITF7Tr3a1xACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AIfrBm5kAMH2cI8BAGKsbR52Yj2ZyRBj8fybyrCPEg15Kg4Ne2LGSKxM-WnEce5gVwiluZijYEWJ8P_lNnKQ4I8QRqwKw68AhHyujKJ6ONvACD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIDJMS6lBxVTSXFXoSysVp0G7mLlBO3oJhDhdt2_MeF_jwIAyiZQrGE_rX7-fMmHhi0w0alTwk-kMl9pcqHOPJY6IYCPAgj05mbh3heIPRGLIyBSpM2ogBL0VoXlEmW3Kebjy938AI8SDS_oDWoE4cPmiWBcq7DTP7ogwVA0aFcKS42POwhrVIEgjxIII8CG1OD0iLOJA9IIuyHxaOmLNKr3Pd-orWulwTsKSmCPEgNEUc_F6ktAagdk6E0YYnsUqC9pt3K2VrR-uJIc2_i_AI8CD20EgCzlmnqHeccy6BW9Ifsp_dRylp022jVxy290j6EgjxIBButcXheltB9r5q_SiVaYiPmqtX1_20ZNerwgnGiSE_CPEgoIuFmZyvZNn9xG6qppiK_mJT40FHqHfjKvxdbYaYwQAI8CDTURm5psgkpndkZlRIia_PxrzHEbIi4fWR0w8YEe9YLAjwIMIc4xq7iJ2YP27EtWYUvEm4-TQD7cayDq2XvZh74n3BCPAg3v2QXfNkDO6Xzu9061umH0rhjRfHBKza3uG2nPQbpd8I8CCtNZgmApuKULvPC9nsMCaM05arV-F3o5FTlnJCnRvdMgjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3WablSaV64Wfn7Pmby5WLyI-A0I8QRqwKw78AhITF7Tr3a1xACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AIfrBm5kAMH2cI8BAGKsbR52Yj2ZyRBj8fybyrCPEg15Kg4Ne2LGSKxM-WnEce5gVwiluZijYEWJ8P_lNnKQ4I8QRqwKw68AhHyujKJ6ONvACD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn"]},"log":{"leaf_index":"553","tree_size":"2123","proof":["d5ebed3381187df4e9f3271354c05c87c8dc14c634957220fda41fb77e02a45d","f8ab0bd5d8b4da7948e8df5cb3fd91bc707ac975400bff719644aae2c7bcb220","a8d148758eba33a37f37aa73d9d7b62dc7d7bae8589f5759593cc48a612f94b6","ecdb87f5ff1f2600ed622805fe32a9fbc84c69511e0b2eadf990c34fab4d807c","d49b32ff02609ac3aaa57e2cacdc03bd425145ce57cfb29b7644a1d64ab6c701","d51179e20cce7f7c89be598cfe03ff1e6b6aed9abab6697dc817cad0f13d732c","3e2f42ad699bdec235da1d2bfa42533abf32590a41496bba393972651e8eacb7","b0e100ab5ebcce5446b0b2d4ff6ac7d35040cb0c821edb28792fd1c81ccd1f6e","9f0db5cb2ee9169ea5d56ed30f68fa386251991cc487135832bf8c105dc92c96","14108339881e6713df1e6d34582069c609e80460dc60638e661361aa4403ff51","ec3fa24572dee1df200ec665f3e3244d925b199f0f84e225b820c3b66bd7b094","addcf2e0ff7974e4aa99af5e30d409f90d9f4311a4d85f5baf3e125eeb45b4c1"],"checkpoint":"pubphys.com/log/v1\n2123\npXVcluz7BF4vgChQs6lShuU0386gCH0RxrC1sxyE3rI=\n\n— pubphys.com/log/v1 JFPwIOLzsUD22XoTVyTfk/FMVj/u3f3DxZk4V/Ws10KVSS+8WQSwhunQ//EAhyS9Td5CyM0E++85GMezmKd8240j9Q8=\n","promise":null},"orcid_key_evidence":[],"attesting":null}