{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"faa96634d4a95ca4743cb71f309a4f25812c0dee2eb3a1fe87eb88e175931546","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["2e2cb3b3d39c106f48104497b934f43bde51b2dc87fcc9ca0479e316e388e270","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"a95f6aaf84323403890091e4988c9d9b13bec20380fa95007a8b6ecd5eb3023a","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":"2","parents":[],"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 $V(r) = g_s^{N} g_p^{N} (\\hbar^2/(8 \\pi m_N)) (\\sigma . r_{\\mathrm{hat}}) (1/(\\lambda r) + 1/r^2) \\exp(-r/\\lambda)$ 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":"2e2cb3b3d39c106f48104497b934f43bde51b2dc87fcc9ca0479e316e388e270","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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"659dbe5ddc115de33a20c36461d2f85b2edc8ad846a8d28ece92f6bfa26327a7","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7a666cf65a54702344866cac9419eb229a25f1e30454a96816f447d6cb7d39fa","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"jHMv_zsjBjYXX_D8-siLlv0EpVw9dfSlVeMkb1gqj8v-oJ5LjufYDfto3b8sbL6IY6XNvZ-2dOz-JNTYv2RJDw"},"schema":"pubphys.envelope/1"},"record_hash":"659dbe5ddc115de33a20c36461d2f85b2edc8ad846a8d28ece92f6bfa26327a7","leaf_index":2284}