{"paper":{"title":"Anthropic Bound on Dark Radiation and its Implications for Reheating","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph","hep-th"],"primary_cat":"astro-ph.CO","authors_text":"Fuminobu Takahashi, Masaki Yamada","submitted_at":"2019-04-29T18:00:03Z","abstract_excerpt":"We derive an anthropic bound on the extra neutrino species, $\\Delta N_{\\rm eff}$, based on the observation that a positive $\\Delta N_{\\rm eff}$ suppresses the growth of matter fluctuations due to the prolonged radiation dominated era, which reduces the fraction of matter that collapses into galaxies, hence, the number of observers. We vary $\\Delta N_{\\rm eff}$ and the positive cosmological constant while fixing the other cosmological parameters. We then show that the probability of finding ourselves in a universe satisfying the current bound is of order a few percents for a flat prior distribu"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.12864","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}