{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"da5625e1e6164cc1ad9934f48143a993c11889c665ab7f966c3a792dee1ba494","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"bc0a690fc541ab6a2f414a4c2d9bc303c1ad83cd70bb70d447683bae307d4477","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"hep.neutrino-fog.atmospheric-flux","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"For heavy dark matter, the main neutrino background comes from cosmic rays hitting the atmosphere and producing low-energy neutrinos, whose number is poorly measured. Better knowledge of this flux decides how deep heavy dark matter searches can go.","posed_since":"","precise":"The CEvNS background for WIMP masses above about $100\\,\\mathrm{GeV}$ comes from atmospheric neutrinos with $E_\\nu$ below about $100\\,\\mathrm{MeV}$, where the flux has never been measured directly and model uncertainties are of order 20 percent. The quantity is this flux, with its site and solar-cycle dependence, to about 10 percent precision. An answer is a measurement or a validated calculation of the sub-$100\\,\\mathrm{MeV}$ atmospheric $\\nu_e$ and $\\nu_\\mu$ fluxes at underground laboratory sites.","problem_ref":null,"references":"","settled_by":"A measurement of low-energy atmospheric neutrinos in a large detector (e.g., JUNO, Super-Kamiokande with gadolinium, DUNE) or by the first atmospheric CEvNS detection in a dark matter detector.","status_note":"Fan, Liu and Zhou (Chin. Phys. C 49, 103001, 2025) estimated the atmospheric flux at CJPL to be about 30 percent lower than at LNGS, so the fog boundary for heavy WIMPs is site dependent.","title":"How well is the sub-100 MeV atmospheric neutrino flux known?","topic_ref":"8aa34dbf8fe622dfe44455a4a52ccd521c5275a918d302f3967b566a3c2ae8e9"},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f91e3b9a1a36c591a827259faf3eb3291e96015fa88a76864999a8123df29780","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"6e2545d3a2b8c886c5189d72ad9f5775c31734e5b16f84212d08b5b25c4c48cd","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"U2pxA_zpSNSC8OUuagTeaIcyHFd_S2eP1VuKJuNFykE9rWdnD8jZjmAyvO-U5eN4zL58sZlvLKRGNdAkTs2sDg"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIbiVF06K4yIbFGJ1yrZ9XdcMXNOWxb4QhLQi1slxMSM3xIG4ScXV58t8_CphlvXygr1Z2fqd_pOLwbmnMtsjwDVPcCPAggM3a2oeI3Os0IB4JGqVGAquiU2WUwry01c87weyIPvQI8SBGK4WPrprONxEOnk6sjX5_HvHu5so5D6HyKOcUr6COjwjxIAfy2lnasld80Ua8tH3f4bhW7NwXu_C1_9cQWCgzWp7HCPAgdFhGyFZuiRz77UHiprfFeyy5eIYRHtIEscrQbbioCR8I8CBeBEbdhAOCGP-uKZkISqBYiwB2dxfS2rmloIKLuJ-NMAjwIOWqEfhSRhf7wTNJBWZNvS1W6_5VVHVzwolNT4ElNhRVCPAgY62IgQuQJxN3qyWDdsSTATEfW2keFBOuI8VrhYhkHBMI8SB8izl_Yn9kR2zBmnu-HVjv452ytRQyuNX-opb_OJzg_gjxINBAKCf3cKChW811B6TkfdlxdONUiLQA88uJMnPer4KuCPEgytIBB3x7TFDT-XqOV-9vpqw1NKoAu0dhtsCbAMql2L0I8CCtNZgmApuKULvPC9nsMCaM05arV-F3o5FTlnJCnRvdMgjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3WablSaV64Wfn7Pmby5WLyI-A0I8QRqwKw78AhITF7Tr3a1xACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AIfrBm5kAMH2cI8BAGKsbR52Yj2ZyRBj8fybyrCPEg15Kg4Ne2LGSKxM-WnEce5gVwiluZijYEWJ8P_lNnKQ4I8QRqwKw68AhHyujKJ6ONvACD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEI42FseeZY0IF_IKGyMkkum2KKbh700N_3WRvQQnAvc4bwIONnz7BJ-j7zfNR3qR2SMH9LNA72jrIe38jF0N--VtggCPAg7rAITwU-3_jhFrr5vte_v-lviI2kpMbez4-W8KUJcUsI8CASEca4qVmq8wYVC-cUu6KeY-86Tb5r1sokKTEwKe682QjwIPGcWTliS3UN3DCpbgsJM9PHEz4WyWxeMxCTXTAUDnssCPAgwi-es3N1VshureEAOoM3tnr7y81ApSyuwXIdNq2xI2cI8CD_YgLSfBSD9rQUpTi7tXR6EE_5qC7acOQy6wTGUQq3gAjxILxzQWMAmvaultZlg8E3OUpGfSrLm6L_gGXyaZDMO7ZVCPEgX1ct-J5utS2Y9i_MQF8whgQqggfdpWZjb4EXThxsbjcI8CCoahAZNQNYu2Y_acHP7f8i7DMCAPi7QeYPsDQmFOUZcgjxIOUdEg6sSGuGAwm6byKNwNSH-CaFtay_ppzVi8InqIsBCPEgUZCxxJx-baWw4JFRfzCCtSjPn4ATBx_3FQi1O2Yo4-8I8SAQuuTPkAGyvS_wKMy9BtKvnki2puESdY2vXem8hT1uIQjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3WablSaV64Wfn7Pmby5WLyI-A0I8QRqwKw78AhITF7Tr3a1xACD3-MNLvkMjiwraHR0cHM6Ly9ib2IuYnRjLmNhbGVuZGFyLm9wZW50aW1lc3RhbXBzLm9yZ_AIfrBm5kAMH2cI8BAGKsbR52Yj2ZyRBj8fybyrCPEg15Kg4Ne2LGSKxM-WnEce5gVwiluZijYEWJ8P_lNnKQ4I8QRqwKw68AhHyujKJ6ONvACD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3Jn"]},"log":{"leaf_index":"1567","tree_size":"2123","proof":["6581917ac608f6fa2ba89ba50c66fed0c3bbb68bbb8f4afac1e13964fe4b46f1","4fcc12e106f034c27602bd8a476aad7eab8acead8c57d0d8fb34357f1aa273ee","d6abc1f73a8b8a53a0fca7890d9771ebfe11c91005d6ff7f0a721ac0b9c1e30f","bf7ce09ff666fb4e15298c446a9a2f9b62f0c9ca04b81f5d5e66cb38cdd74556","13e8057fe8bd47e34b1ec4be693d7ac9306f8f8f6e791feab262559025336429","f434f31261179c4194dbffa33ef8d7720493bbd229370b750f06b1bd27da2a95","90c76f05178b1e645281056245084c61b577ed1075df4912315bbc4e2c22997f","b78ddae6ec4f50645dafadd88148aea3eac280e472349d3dbe77576e43fa2780","a8cef064ef9c15524538954d820d60e39424932bbb86df562c6b87106df2eda9","35f1d0a5e69da98f9992a5251e4e3df1933c2f26543c7a40b2681ecfa194443a","2b97406e15e4d451a5450b3b53b677749fe0fa759579146dbfa1544c1e61a0ed","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}