{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e5ba642efcddab622347bde29be2f50f69a6ce3c40fca63bff169045d64918c1","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":["ai:gpt-5.5"],"kind":"seed"},"parents":["b0c35cf657828db33d381df922b2bb6579dcb967462e786be725380c69a74e28","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"c9ce128d50f8413ac48c39c84e548a538353434f232fa49180e8615e4c603db9","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":["ai:gpt-5.5"],"external_id":"nuc.exotic-hadrons.pc-spin-parity","kind":"well-posed","literature_status":"open","n":"2","parents":[],"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 $\\Sigma_{c}+ \\mathrm{anti}-D*0$ threshold. Determine $J^{P}$ of each from a full amplitude analysis. Answer: $J^{P}$ values; the $\\Sigma_{c}\\ \\mathrm{anti}-D*$ molecular picture predicts $1/2-$ and $3/2-$, with the ordering set by short-range contact terms.","problem_ref":"b0c35cf657828db33d381df922b2bb6579dcb967462e786be725380c69a74e28","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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"a82e4d10cd86fc96b429a64300b78c3eb7c9c1706bf0e306a7a3bdfe831dd47e","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"6b71ca4dfc8852d943b798fcd1520ce5c3ed85ffce59f506c45a2fbe7c1cb84b","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"lvur5G0FhmI6u8q_uOo0bBWsphqQzUQYq-caLWfOn4qnRJhpYxyKOW_bRqtCwI-mF5NO3EhK_PPAc1t1h1hlCQ"},"schema":"pubphys.envelope/1"},"record_hash":"a82e4d10cd86fc96b429a64300b78c3eb7c9c1706bf0e306a7a3bdfe831dd47e","leaf_index":3494}