{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"5a5e0b068657ad177f2252953f94eb78b062482ab252374f6df731ef278abba3","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"d7148ebfd2289868719d2de3e5d1f5552c8ef3bd6ff429dd1db33841b06e78db","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"classification","assisted_by":[],"external_id":"nuc.exotic-hadrons.compact-or-molecular","kind":"phenomenon","literature_status":"contested","n":"1","parents":[],"plain":"Many exotic hadrons have masses very close to the combined mass of two ordinary hadrons, which suggests a loosely bound molecule of two mesons or of a meson and a baryon. Others argue they are compact objects in which four or five quarks are tightly bound together.","posed_since":"2003","precise":"For chi_c1(3872), $Z_c(3900)$, $T_{cc}+(3875)$, $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$, determine the structure: the weight of the two-hadron component (compositeness, between 0 and 1) versus compact diquark-antidiquark or pentaquark components. Answer: a classification supported by pole positions, line shapes, production rates in high-multiplicity pp collisions, and lattice QCD finite-volume spectra.","problem_ref":null,"references":"","settled_by":"Lattice QCD coupled-channel scattering at physical quark masses giving pole positions and residues, matched to high-statistics experimental line shapes.","status_note":"The LHCb pentaquarks (2019) and $T_{cc}+$ (2021) are commonly described as molecules, but compact interpretations persist and no single observable discriminated between them as of 2026.","title":"Are near-threshold exotic hadrons compact multiquarks or hadronic molecules?","topic_ref":"0a95c0555eb6bb05e3999da7d5dca17d55ffdaf922ee81ba9f8dcd197324eda0"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"92f81305b482b6400d3856a69e01288ef6a9ddb630b25dfa8b749462fb37756b","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"e7ebf70f657b7bde592b0df9afba8a1c4865a00e7a32dafac488406f6c8c4987","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"vL2ySNDkoCbjH4QZjBjR79KykYgVJI8VSEDil7x7Blsa4Hyrc0FtyNPIBxJxKcR1kp5tNvYSgWgt-In7fh6vCA"},"schema":"pubphys.envelope/1"},"record_hash":"92f81305b482b6400d3856a69e01288ef6a9ddb630b25dfa8b749462fb37756b","leaf_index":1745}