{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3dd8e633a5e0e7aa4a9777ff305f6ee35a2420a2919114ebf459a659b2cbad41","created":"2026-10-03T07:18:05Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["32374ef8644e111942e945441cdc3d16ba405fbc4f99d22ad2df20e300814dd3","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"aaecb2979ff638228c86fc45c87c1b7fc9240461f0233677b70cd29c2b761ccb","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"hep.accelerator-dark-sectors.light-thermal-dm","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"32374ef8644e111942e945441cdc3d16ba405fbc4f99d22ad2df20e300814dd3","relation":"special_case"}],"plain":"If a hidden particle of mass between about an electron and a proton mass was produced thermally in the early universe, a predicted coupling follows. Electron beams on targets can test that prediction directly.","posed_since":"","precise":"Test the thermal-freeze-out target y = epsilon^2 alpha_D (m_chi/m_A')^4 for scalar and fermion dark matter with $m_{\\chi} \\sim 1\\,\\mathrm{MeV} \\text{ to } 1\\,\\mathrm{GeV}$ coupled through a dark photon, using missing energy and momentum in $e- N \\to e- N A'$, A' -> chi chi-bar. An answer is a signal or exclusion of the thermal target for the main benchmark models.","problem_ref":null,"references":"","settled_by":"LDMX and NA64 (electron and muon modes) reaching the thermal targets across 1 MeV to $\\sim 1\\,\\mathrm{GeV}$.","status_note":"NA64 excludes thermal targets for some benchmarks at the lowest masses as of 2024 to 2025.","title":"Do missing-momentum experiments find MeV-GeV dark sector production?","topic_ref":"09c9143d4a1d1ccd3178fe390a3258b114047adf03da6b4f6f24c823883e4f74"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5ed7f5391eaa7b84c1b3d7e397b74c4ef47a418820f6dcac9242d4f73b5b3fe0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"d959cb18f12255131dc569ef9881a4cc55e0a54e694746abfb0de9ea0fa87a7d","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"oyz1sCUZItUk-_H1DTSdcWFvpLs0tRg6IeL-VVEs77ISu7I8IxwDycdAyk-MOCo4dphO8y1nym6C_vHE5h_HCA"},"schema":"pubphys.envelope/1"},"record_hash":"5ed7f5391eaa7b84c1b3d7e397b74c4ef47a418820f6dcac9242d4f73b5b3fe0","leaf_index":1524}