{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"f6b4818017a3fc67b5da1c526315fe3eaa018e18130ac32e06d9522b1784fa98","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["1b32ad92d06914bc07abfbf37a6e7047a2c33a479e25fe7034faf994e72b2dcc","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"0acbeb0b86515154d55d50882c8d672e1cc34a0cf2dc657127bad283f81147bb","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"hep.low-energy-excess.calorimeter-mechanism","kind":"phenomenon","literature_status":"contested","n":"2","parents":[],"plain":"Crystals cooled near absolute zero record many more small heat pulses below a few hundred electron volts than expected, and the rate fades over weeks after cooling. The question is what inside the detector releases this energy.","posed_since":"","precise":"Cryogenic calorimeters (CRESST $\\mathrm{CaWO_4}$, $\\mathrm{Al_2O_3}$, Si; SuperCDMS-type Si and Ge; NUCLEUS; EDELWEISS) observe a rate $\\mathrm{d}R/\\mathrm{d}E$ rising steeply below about 200 eV, uncorrelated with particle backgrounds and decaying after cooldown. Candidate sources include stress relaxation at holders, glue and sensor films; dislocation motion from differential thermal contraction; and annealing of radiation-induced lattice defects. An answer is a mechanism that reproduces the energy spectrum, the time dependence, the material dependence and the sensor-geometry dependence, confirmed by a controlled test that turns the excess on or off.","problem_ref":"1b32ad92d06914bc07abfbf37a6e7047a2c33a479e25fe7034faf994e72b2dcc","references":"","settled_by":"A detector in which removing or adding the hypothesized source (e.g., stress in the holder or film, or a defect population) changes the excess rate by a predicted factor.","status_note":"In 2026 NUCLEUS (Eur. Phys. J. C 86, 831) found slower cooldown lowers the initial rate and the rate decays as a power law independent of particle background; stress-relaxation (Nature Commun. 2024), thermal-contraction (2026 preprint) and defect-annealing (Phys. Rev. Mater. 2025) explanations all remain under discussion.","title":"What microscopic process produces the excess in cryogenic calorimeters?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0c1d4584c41c13df3659def77da8029e1864880ac5300e5ec9fc2b0c381f08e6","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"52c63465541cb4a4d154d98d7ecbd8dcd29aadbb280a996d1b404a816ab98ba9","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"fo2pRR5qhdaZrHaRaoJEm0Jr28-kGRv-HbxD-OKWjFQx5d7JVHpsgqXfcge_Z7PjFzpKFd6DDHNXRfwlA9H9Bg"},"schema":"pubphys.envelope/1"},"record_hash":"0c1d4584c41c13df3659def77da8029e1864880ac5300e5ec9fc2b0c381f08e6","leaf_index":3366}