{"paper":{"title":"Near-Resonant Thermal Leptogenesis","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Quasi-degenerate right-handed neutrinos produce the baryon asymmetry down to electroweak scales without resonance.","cross_cats":["astro-ph.CO"],"primary_cat":"hep-ph","authors_text":"Angus Spalding","submitted_at":"2026-02-04T17:07:46Z","abstract_excerpt":"We study leptogenesis in the quasi-degenerate but non-resonant regime. Expanding the CP asymmetry parameter near degeneracy and imposing the conservative non-resonance condition that the mass splitting must be much greater than the right-handed neutrino decay rates $\\Delta M > 100\\Gamma_i$, yields the universal upper bound $\\epsilon \\leq 1/200$, independent of both the effective neutrino masses and the right-handed neutrino mass. We investigate vanilla and flavoured near-resonant leptogenesis and find that successful leptogenesis by right-handed neutrino decays can occur for $M \\gtrsim 100~\\ma"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"imposing the conservative non-resonance condition that the mass splitting must be much greater than the right-handed neutrino decay rates ΔM > 100Γ_i, yields the universal upper bound ε ≤ 1/200, independent of both the effective neutrino masses and the right-handed neutrino mass.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that the imposed condition ΔM > 100Γ_i is sufficient to justify the perturbative expansion near degeneracy while still allowing enough asymmetry for successful leptogenesis; this choice of factor 100 is presented as conservative but directly controls the derived bound.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Near-resonant thermal leptogenesis produces the observed baryon asymmetry for right-handed neutrino masses above 100 GeV without resonance, including during low-temperature reheating.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Quasi-degenerate right-handed neutrinos produce the baryon asymmetry down to electroweak scales without resonance.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"2963b0aacb642a86ccb44a03e8eb119c8f0e90c5db8939e4feb8e5d1d7f0657d"},"source":{"id":"2602.04772","kind":"arxiv","version":2},"verdict":{"id":"3583f450-8e08-4bc1-9933-23b52ded5545","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T07:00:09.781063Z","strongest_claim":"imposing the conservative non-resonance condition that the mass splitting must be much greater than the right-handed neutrino decay rates ΔM > 100Γ_i, yields the universal upper bound ε ≤ 1/200, independent of both the effective neutrino masses and the right-handed neutrino mass.","one_line_summary":"Near-resonant thermal leptogenesis produces the observed baryon asymmetry for right-handed neutrino masses above 100 GeV without resonance, including during low-temperature reheating.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that the imposed condition ΔM > 100Γ_i is sufficient to justify the perturbative expansion near degeneracy while still allowing enough asymmetry for successful leptogenesis; this choice of factor 100 is presented as conservative but directly controls the derived bound.","pith_extraction_headline":"Quasi-degenerate right-handed neutrinos produce the baryon asymmetry down to electroweak scales without resonance."},"references":{"count":61,"sample":[{"doi":"","year":null,"title":"Bound on Reheating Temperature 22 C","work_id":"e5fb4b26-95f2-41c3-99d7-7260ab9f328c","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"In the limitsM i ≫m D the seesaw relation is achieved. We adopt the Casas–Ibarra parametrisation of the Yukawa matrix, which allows us to express the neutrino Yukawa couplings in terms of low-energy n","work_id":"039234ab-bb86-429e-b053-253c5c721ac9","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Rescaling Variables To make the Boltzmann equations numerically tractable it is convenient to introduce comoving variables that absorb the dilution factors due to the cosmic expansion. We define our p","work_id":"76f8439a-aa6d-43f7-889b-211e6975405b","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2001,"title":"Fukuda et al","work_id":"145e0dc9-9eed-4a71-848b-4886cc7995e3","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2002,"title":"Fukuda et al","work_id":"d2551be9-261a-4e53-badf-b8856b52de7f","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":61,"snapshot_sha256":"43c6984e402c8be1829c8168b925358a8949ead3a14e541ed078869f58b93a7b","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"96a359d86a7e9b532c386a0fe810b54092a323b60d04505f3d575e381cfb362f"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}