{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"2e927369e6101418a9ce517c6d85e2c2eb83339a7c326fea0073d9635b0448c6","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["0c1aa5154c21b9d3e75eebffe0face8ea825d4454f506ce7ca07db4dd6fd1518","5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"0dbb7da23a8e4852626ef2d5b3ca914a52e3208870c3a2debc873c5eafbcdf7d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"amo.ultralight-dm-fifth-forces.monopole-dipole-nucleon","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"0c1aa5154c21b9d3e75eebffe0face8ea825d4454f506ce7ca07db4dd6fd1518","relation":"special_case"}],"plain":"An axion could make an ordinary lump of matter push slightly on nearby nuclear spins, as if the spins felt a weak magnetic field that ordinary magnetic shielding cannot block. Nuclear magnetic resonance next to a rotating source mass looks for this push at distances below a millimeter.","posed_since":"1984","precise":"For the monopole-dipole potential $V(r) = g_s^{N} g_p^{N} (\\hbar^2/(8 \\pi m_N)) (\\sigma . r_{\\mathrm{hat}}) (1/(\\lambda r) + 1/r^2) \\operatorname{exp}(-r/\\lambda)$ between an unpolarized nucleon and a polarized nucleon (Moody-Wilczek form), with range $\\lambda$ from $10\\,\\text{micron}\\ \\text{to}\\ 1\\,\\mathrm{mm}$, determine whether $g_s^{N} g_p^{N}$ is nonzero down to the value expected for a QCD axion with a small CP-violating scalar coupling, using polarized He-3 or other nuclear-spin sensors near a modulated source mass (Arvanitaki and Geraci 2014).","problem_ref":null,"references":"","settled_by":"A resonant nuclear-spin measurement near a modulated source mass that reaches the QCD-axion band in $g_{s}^{N} g_{p}^{N}$ over this range, or detects a signal with the predicted distance dependence.","status_note":"","title":"Axion-mediated monopole-dipole nucleon force at submillimeter range","topic_ref":"65dd591d9a6aea57b124c4aa9efd99b0deceb1c7733b697b5b72544d315d1ba0"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"2e2cb3b3d39c106f48104497b934f43bde51b2dc87fcc9ca0479e316e388e270","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"a7c57c1182f987234dc98cfc4ee129f55a2101bf9c81ec2d002389612d5fd476","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"ZS5PjxI92FwHXqCUhGHCg9A7l_YQAmNUJJGJbhv0GSI9q2byYr0J4AznJjFQ2Y65IkG7YEZHblSGjv5e3xI6Dw"},"schema":"pubphys.envelope/1"},"record_hash":"2e2cb3b3d39c106f48104497b934f43bde51b2dc87fcc9ca0479e316e388e270","leaf_index":471}