{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.topic/1","content_sha256":"faa02e27e9f5e3dfe8f4c7c2ea37a5ac8510ac99752c3b6c9351bf79b5784562","created":"2026-10-03T07:17:52Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":[],"salt":"c440fccf3998d64dadfc116588a8a125c0e7885e6f556621bc65d98d1f7cf122","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"topic"},"content":{"external_id":"nuc.proton-structure","field":"nuc","n":"1","review_cite":"Ji, Yuan, Zhao, Proton spin after 30 years: what we know and what we don't?, arXiv:2009.01291, 2020","review_link":"https://arxiv.org/abs/2009.01291","review_verified":"true","summary":"The proton is made of quarks and gluons, yet the quarks' own spins supply only about a third of its spin and the quark masses only about one percent of its mass. Where the rest comes from, and exactly how large the proton is, are still being measured.","title":"Proton spin, mass and charge radius","topic_ref":null,"why":"The proton is the simplest stable bound state of QCD (quantum chromodynamics, the theory of quarks and gluons), so its basic properties are the first test of how that theory builds matter."},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"43e6b835146db14bd1b426a6a865acb8bf50720a1000b6a2c5c5d637adc5063d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f028315143190f514df8ae8b5ac4ec95e9d497865dc0ee98260e04f3ee3afabb","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"rcsZxUiA2ZaifSFbx5XOW290GGah7noABImyX8H8Da2CZ_kU96m6TuYPlczUaqRU58ScwQG2jraKk0sS3XSgDQ"},"schema":"pubphys.envelope/1"},"record_hash":"43e6b835146db14bd1b426a6a865acb8bf50720a1000b6a2c5c5d637adc5063d","leaf_index":291}