{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"ada1c6472db6f56255550e9e329ed75f0e64ea2b28b4b751f969844e59047898","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011","92f81305b482b6400d3856a69e01288ef6a9ddb630b25dfa8b749462fb37756b"],"salt":"697caecbcaa8fb35da83185bd131a808756596f85ea9d4606070a00af370c81a","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"nuc.exotic-hadrons.pc-spin-parity","kind":"well-posed","literature_status":"open","n":"1","parents":[{"note":"","parent_revision":"92f81305b482b6400d3856a69e01288ef6a9ddb630b25dfa8b749462fb37756b","relation":"special_case"}],"plain":"LHCb found in 2019 that one pentaquark signal is two close peaks, at 4440 and 4457 MeV, both just below the energy of a charmed baryon plus a charmed meson. Molecular models predict spins $1/2$ and $3/2$ for this pair while compact models give other patterns, so measuring the spins tests the pictures.","posed_since":"2019","precise":"$\\mathrm{Pc}(4440)+$ and $\\mathrm{Pc}(4457)+$ appear in $J/\\psi\\,p$ from $\\Lambda_{b} \\to J/\\psi\\,p\\,K-$ (LHCb, PRL 122, 222001, 2019), about 20 and 3 MeV below the Sigma_c+ anti-D*0 threshold. Determine $J^{P}$ of each from a full amplitude analysis. Answer: $J^{P}$ values; the Sigma_c anti-D* molecular picture predicts $1/2-$ and $3/2-$, with the ordering set by short-range contact terms.","problem_ref":null,"references":"","settled_by":"A full amplitude analysis of $\\Lambda_b \\to \\mathrm{J}/\\psi\\, \\mathrm{p}\\, \\mathrm{K}-$ with LHCb Run 3 statistics, cross-checked in a second production channel.","status_note":"No spin-parity determination of either state had been published, to our knowledge, as of mid-2026.","title":"Spin and parity of the Pc(4440) and Pc(4457) pentaquarks","topic_ref":"0a95c0555eb6bb05e3999da7d5dca17d55ffdaf922ee81ba9f8dcd197324eda0"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"b0c35cf657828db33d381df922b2bb6579dcb967462e786be725380c69a74e28","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"ace3c60c85975ddb190e4acccc832b66dfcff2785bdd1eddc04ab405fdf82c86","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"Z_wJjRwhyfM0vjUmxSSruVxx2LUvIat_KEgcOTQ9clg1Dq3_9jXbfjMdOZ6S-d4beAhu95AvjzBcxyt74SuyBw"},"schema":"pubphys.envelope/1"},"record_hash":"b0c35cf657828db33d381df922b2bb6579dcb967462e786be725380c69a74e28","leaf_index":1747}