{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"531207cb802c24404e8a5e7b1438dbd9cd363ee18b4cc4a17dc04c08880b6635","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"d0a9ccd7b5844ce080711e9fe79822e2bc86a1a24f43fe1bff562f84c12d91de","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"nuc.neutrino-nucleus.pion-production","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"In the few-GeV range many neutrino collisions make a pion, often through a short-lived excited nucleon called the Delta. Measurements from different experiments and the models used to describe them do not agree, especially for slow pions and small momentum transfers.","posed_since":"","precise":"Construct a model of charged- and neutral-current single-pion production on 12C, 16O and 40Ar for $E_{\\nu} = 0.5\\ \\text{to}\\ 5\\ \\mathrm{GeV}$ that simultaneously reproduces MiniBooNE, MINERvA and T2K pion kinematic distributions, including the low-$Q^2$ suppression and the pion absorption and charge exchange in the nucleus. The answer must identify the physics (in-medium $\\Delta$ properties, nonresonant background, final-state interactions, flux normalization) responsible for the inter-experiment tension.","problem_ref":null,"references":"","settled_by":"A single model, constrained by pion electroproduction and hydrogen or deuterium neutrino data, that fits all nuclear-target pion data within quoted uncertainties.","status_note":"","title":"Reliable models of neutrino pion production on nuclei","topic_ref":"b26dbf879b3c8d9dff63a9d6b76e31cb28a6d3c51cf2e1a87d88d68d65a23459"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f37258440f5eea6b92f608d1bc5bee4825cf0d2a1d193e1f29a4d2312b5ac60d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c88ca6a9d9043a1c9eb182dd531f497d5514a031c0e838ee527c8130bf08472d","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"UEtqI4EHgmMZXbUdRGhIyGsQPumqP3yBJXUiFfcdS41plD_mZf-qVuw0lcoZSTQ8WV88a_XwN2ddGq2a5lQtAw"},"schema":"pubphys.envelope/1"},"record_hash":"f37258440f5eea6b92f608d1bc5bee4825cf0d2a1d193e1f29a4d2312b5ac60d","leaf_index":1775}