{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"8f5d8a108d2e9fcf4dfd25f3987a8ae9b3177797043b705161f6ca8fa7b0fd76","created":"2026-10-03T07:18:07Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"9ee9df14c1bd67356da1f16c067eb9b3f4919e7570728a4ce0770a8974e2d3c1","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"nuc.ab-initio-nuclei.nn-binding-lattice","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"The deuteron (a bound proton and neutron) is held together by only 2.2 MeV, while two neutrons do not bind at all. Lattice QCD calculations at heavier-than-real quark masses disagree with each other on whether two nucleons bind.","posed_since":"","precise":"Compute the $I=0$ (deuteron) and $I=1$ (dineutron) S-wave nucleon-nucleon phase shifts and pole positions in lattice QCD at the physical pion mass, with continuum and infinite-volume extrapolation. Answer: deuteron binding energy (experiment $2.2246\\,\\mathrm{MeV}$) and the $1S0$ nn scattering length (experiment about $-18.9\\,\\mathrm{fm}$), plus resolution of the dependence of results on the choice of interpolating operators found at $m_{\\pi}$ above $300\\,\\mathrm{MeV}$.","problem_ref":null,"references":"","settled_by":"Variational lattice QCD spectra with complete two-nucleon operator bases at several pion masses down to physical, converted to scattering amplitudes with the Luscher finite-volume method (which maps energies in a finite box to phase shifts).","status_note":"A 2025 calculation with a large operator basis at $m_{\\pi}$ about $714\\,\\mathrm{MeV}$ found no bound dinucleons (BaSc collaboration, arXiv 2505.05547), contradicting earlier deep-binding results obtained with compact hexaquark operators.","title":"Two-nucleon binding from lattice QCD at physical quark masses","topic_ref":"2e3c9bbdd2ce5849bb4ba420a815301d70db5fbf0341e1a0ed3d81994b4e4b35"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f968ac34ae2bb2b59fa111e56bac5bdeb7fd284f3eda7b96713a714c333197dd","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"998fdf08d4310aa79936bd183738d90c281e2d727e90f95b1658c18322ad6233","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"yQ3Fgh7FrnYmOghotOL2JJBO_emdOBIU8Mbyz8P-Y-d6H51WqT45tFg4mKyJaVvC1oqNklI3fgtK1u5Aa8jrBg"},"schema":"pubphys.envelope/1"},"record_hash":"f968ac34ae2bb2b59fa111e56bac5bdeb7fd284f3eda7b96713a714c333197dd","leaf_index":1733}