{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"4b24a5f54a4d3c50223d00f5296be2930043768914c8ea80a3f79e3f1857245a","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["45ca3224045fe4a750c1a11a5bfc843358f7b0115700613cf7f290e3e9ad1baa","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"8761e52f005a8476a8439f7a22aa60a7b1e2ef68025afce5ed3b4a37044c7b9d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"hep.sub-gev-detection.daily-modulation-anisotropy","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"In a crystal that responds differently along different directions, the signal from dark matter should rise and fall once a day as Earth rotates, while most backgrounds should not. This could distinguish a real signal from the unexplained excess of small events.","posed_since":"","precise":"For sub-GeV dark matter scattering via phonons or electrons in anisotropic crystals (e.g., $\\mathrm{Al_2O_3}$, hexagonal BN, graphene-like or Dirac materials), the rate $R(t)$ modulates with sidereal period because the dark matter wind direction rotates relative to the crystal axes; predicted fractional amplitudes reach tens of percent in some materials. The question is whether a modulation of this size can be measured at sub-eV thresholds with exposure below about $1\\,\\mathrm{kg}\\,\\mathrm{yr}$, given present low-energy excess rates, and whether the excess itself shows any sidereal modulation.","problem_ref":"45ca3224045fe4a750c1a11a5bfc843358f7b0115700613cf7f290e3e9ad1baa","references":"","settled_by":"A sidereal-period analysis of a low-threshold anisotropic-crystal data set with known orientation, giving an amplitude limit or detection at the predicted level.","status_note":"A 2026 preprint (arXiv 2606.04091) estimated halo-model uncertainties of 1-100 percent in single-phonon rates across the mass range, which enter the modulation prediction.","title":"Can daily modulation in anisotropic crystals identify light dark matter?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"8a57a159205f06f13119b1b3f866c5911ada0986629880ce62ac2522d5383c17","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8271aecb724200ebe17220f7503a44158fe1cf0d66d4575c49203c4614517f67","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"8DyDUr0pxeeqliDx_9gyacudhTZeCY2F6SrugzXefDOSRDmwarkpGH4c_gdQaOhdx4u1FoSFbDiP7VfYuzufBg"},"schema":"pubphys.envelope/1"},"record_hash":"8a57a159205f06f13119b1b3f866c5911ada0986629880ce62ac2522d5383c17","leaf_index":3390}