{"paper":{"title":"Big Bang For Your Helium Buck","arxiv_id":"2609.13140","primary_cat":"astro-ph.CO","submitted_at":"2026-09-11T17:57:59+00:00","version_compiled":"v1"},"notice":"Every quoted sentence is the authors' text from the arXiv listing abstract. Labels and probabilities are the outputs of classifier-1.13.0 on the question bank abstract-p1-20260923, exactly as returned. No sentence in this record was written by a language model.","schema":"pith.compiled-record/v0","status":"compiled","abstract":{"source":"arXiv listing abstract v1","sentences":[{"i":0,"p":0.8,"id":"s0","own":true,"role":"contribution","text":"We study the implications of a recent measurement of the primordial helium fraction from the Large Binocular Telescope for cosmological inference from the cosmic microwave background.","hedge":{"p":0.7,"label":"asserted"},"own_p":0.6,"main_claim_p":0.05,"quantitative":false,"quantitative_p":0.06,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.0,"background":0.2,"limitation":0.0,"future_work":0.0,"contribution":0.8,"interpretation":0.0}},{"i":1,"p":0.82,"id":"s1","own":true,"role":"result","text":"We show that LBT establishes the robustness of cosmological parameters to theoretical assumptions about big bang nucleosynthesis: its empirical calibration of the helium fraction enables constraints on cosmology and inflation that are agnostic to BBN but as precise as those that instead enforce standard BBN predictions.","hedge":{"p":1.0,"label":"asserted"},"own_p":0.89,"main_claim_p":0.81,"quantitative":true,"quantitative_p":0.85,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.82,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.02,"interpretation":0.16}},{"i":2,"p":0.49,"id":"s2","own":true,"role":"result","text":"Future CMB surveys require at most a marginal improvement in precision over LBT to maximize their BBN-agnostic constraining power when the radiation density is free (and no more than a factor of two improvement across all cases we consider).","hedge":{"p":0.84,"label":"asserted"},"own_p":0.84,"main_claim_p":0.28,"quantitative":true,"quantitative_p":0.98,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.49,"background":0.0,"limitation":0.0,"future_work":0.17,"contribution":0.0,"interpretation":0.34}},{"i":3,"p":0.81,"id":"s3","own":true,"role":"contribution","text":"We then apply the LBT measurement to a number of scenarios that feature new physics in BBN and the CMB.","hedge":{"p":0.92,"label":"asserted"},"own_p":0.91,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.06,"role_probabilities":{"gap":0.0,"method":0.19,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.81,"interpretation":0.0}},{"i":4,"p":0.89,"id":"s4","own":true,"role":"contribution","text":"First, we constrain nonstandard radiation sectors (interacting and free-streaming) and search for evolution of the radiation abundance between nucleosynthesis and recombination.","hedge":{"p":0.78,"label":"asserted"},"own_p":0.9,"main_claim_p":0.04,"quantitative":false,"quantitative_p":0.07,"role_probabilities":{"gap":0.0,"method":0.11,"result":0.0,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.89,"interpretation":0.0}},{"i":5,"p":0.65,"id":"s5","own":true,"role":"result","text":"We then test models that alleviate the Hubble tension and the tension between CMB and baryon acoustic oscillation data, including self-interacting light relics and varying fundamental constants; LBT precludes most but not all of the models we consider via their effect on BBN.","hedge":{"p":0.98,"label":"asserted"},"own_p":0.92,"main_claim_p":0.08,"quantitative":false,"quantitative_p":0.21,"role_probabilities":{"gap":0.0,"method":0.01,"result":0.65,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.33,"interpretation":0.01}},{"i":6,"p":0.87,"id":"s6","own":true,"role":"result","text":"Finally, we use the LBT measurement as an indirect but independent test of the neutron lifetime anomaly, inferring values that are consistent with \"bottle\" experiments and $2.4 \\sigma$ below \"beam\" experiments.","hedge":{"p":0.69,"label":"hedged_possibility"},"own_p":0.93,"main_claim_p":0.08,"quantitative":true,"quantitative_p":0.99,"role_probabilities":{"gap":0.0,"method":0.0,"result":0.87,"background":0.0,"limitation":0.0,"future_work":0.0,"contribution":0.12,"interpretation":0.01}}]},"compiled":{"main_claim":{"p":1.0,"text":"We show that LBT establishes the robustness of cosmological parameters to theoretical assumptions about big bang nucleosynthesis: its empirical calibration of the helium fraction enables constraints on cosmology and inflation that are agnostic to BBN but as precise as those that instead enforce standard BBN predictions.","location":"abstract s1","hedge_strength":{"p":1.0,"label":"asserted"}},"provenance":{"route":{"via":"TypeSafe API","model":"classifier-1.13.0","endpoint":"https://api.typesafe.ai/v1/systemone","provider":"TypeSafe"},"packing":"one request per paper","requests":1,"input_tokens":5876,"cost_usd_reported":0.0},"compiled_at":"2026-09-23","bank_version":"abstract-p1-20260923","model_version":"classifier-1.13.0","abstract_states":{"claims_first":0.04,"states_limitation":0.42,"human_participants":0.02,"controlled_comparison":0.28,"randomized_assignment":0.01,"states_quantitative_result":0.97,"compares_with_prior_results":0.88,"mentions_code_or_data_availability":0.02},"evidential_basis":{"p":0.97,"value":"analysis of existing data","probabilities":{"argument":0.0,"literature":0.0,"proof_or_derivation":0.0,"analysis_of_existing_data":0.97,"observation_or_experiment":0.03,"simulation_or_computation":0.0}},"contribution_type":{"p":0.74,"value":"theoretical result","probabilities":{"review":0.0,"method_or_tool":0.03,"empirical_study":0.11,"simulation_study":0.07,"theoretical_result":0.74,"dataset_or_benchmark":0.0,"position_or_commentary":0.05}},"contribution_statement":{"p":0.53,"text":"We show that LBT establishes the robustness of cosmological parameters to theoretical assumptions about big bang nucleosynthesis: its empirical calibration of the helium fraction enables constraints on cosmology and inflation that are agnostic to BBN but as precise as those that instead enforce standard BBN predictions.","location":"abstract s1"}},"coverage":{"tier":"abstract","levels_run":["P abstract"],"not_examined":["full text","figures and tables","references and citing sentences","relations to other papers"],"sources_read":["arXiv listing abstract v1"],"levels_not_run":["S sections","T body sentences","C citations","R cross-paper relations"],"sentences_examined":7,"sentences_in_abstract":7},"measured_accuracy":{"url":"https://pith.science/accuracy","measured_on":"2026-10-02","method":"two independent model families labelled a fresh random sample blind; 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