{"schema":"pubphys.bundle/1","record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"685c13bc04021033670d93294e557e601cce296c6df06d7b40bc406fc0886198","created":"2026-10-03T07:18:02Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c0861209fd079412aacc5314f5c53e0ce812c12d354b4a175608daf7a2f3babc","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"cosmo.structure-growth-neutrino-mass.reionization-optical-depth","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Free electrons released when the first galaxies ionized hydrogen scatter microwave background light, an effect measured by a number called the optical depth. If it is larger than the Planck value, several current tensions, including the neutrino-mass one, ease.","posed_since":"","precise":"Planck low-multipole EE polarization gives $\\tau = 0.054 \\pm 0.007$. Sailer, Farren, Ferraro and White (2025, arXiv:2504.16932) show that a larger $\\tau$ removes the DESI BAO versus CMB tension in extended models, including the preference for very small or negative sum $m_\\nu$, but conflicts with Planck large-scale polarization. Determine $\\tau$ with $\\sigma(\\tau)$ below 0.003 from an independent large-angle E-mode measurement or from 21-cm and kinetic Sunyaev-Zeldovich reionization histories, and state whether it agrees with the Planck value.","problem_ref":null,"references":"","settled_by":"Large-angle E-mode polarization from LiteBIRD or a ground or balloon experiment such as CLASS, cross-checked with reionization histories from 21-cm and kSZ data.","status_note":"","title":"Is the CMB reionization optical depth underestimated?","topic_ref":"7f5d118cb8a64bd99639aa18f99daf7cb794d9366c6bec82eeea82eef99d0ccd"},"content_withheld":"false","files":[],"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"e78507b756e7a013b0d7f37b3e96ea34143249f0d9d881d9bd947f4a2997d8b4","schema":"pubphys.attested/1"},"id_token":null,"id_token_withheld":"false","envelope":{"attested_hash":"63a23ecbe8b7d23ed8a77f4031edec686032e50e9c2957a6af5c0e02defb1450","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"o5B509ebzIvXloKWPGn3Yqnn9y9nWOSP-qHvrGkr7IfDcsP0SCCPzny_HDFDsqk8P7pnGB_hE9uN-bMfXJUeBg"},"schema":"pubphys.envelope/1"},"ots":{"attested":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIY6I-y-i30j7Yp39AMe3saGAy5Q6cKVemr1wOAt77FFDwIGOwO3gzTkM7VRpZHq1g9bFRLcLOVjKSijZ7Z9itYlHJCPAgv1Syc2SuZIavdixZGW5HD178lsoXKLfGIXmqwlGjl_gI8SC0iuuyAX2l942ly9M_1r4hkMHJ1ijZBT8hBUZXphU2KQjxINmP76YQKWAX3y_usdzY-cH0F_ejQRwIlZlv1tpRFVhXCPAgKb2WiNdzFA-9wChqVq_D5eQo03BRAX8mD_EiouEBWEgI8SCEdAuprEhxQA28-Y-mxpDPnHFYrXFpW_ygfSJlChoA6gjxIDLuS2H5mkQT51okBzSqxvYOZ2DzeEjrKj1FhjpNDRblCPAgOatp97sEGfSkPectTIcXn_UGSclxLvXC9ouOsHYFkl8I8CBPLfD1TsHdjhkyZ9iTm9m5GTCSBT-7GhYUfap1vptsnQjxINBAKCf3cKChW811B6TkfdlxdONUiLQA88uJMnPer4KuCPEgytIBB3x7TFDT-XqOV-9vpqw1NKoAu0dhtsCbAMql2L0I8CCtNZgmApuKULvPC9nsMCaM05arV-F3o5FTlnJCnRvdMgjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3WablSaV64Wfn7Pmby5WLyI-A0I8QRqwKw78AhITF7Tr3a1xP8Ag9_jDS75DI4sK2h0dHBzOi8vYm9iLmJ0Yy5jYWxlbmRhci5vcGVudGltZXN0YW1wcy5vcmcI8CBXWeNiWFWltfHE0nkDXsVKIykUUwuObhsnN-2fvBt98gjwIM5Vf7j68sOFgVysYMc5S09Hho-fqxYW3oQ4oKUX7JpPCPAgaKHHQB3sdd9w1hu4NMh7vmb-p0X2r4uyVKKCj1G7S28I8SAW2Mg6Bzi9ygjrrjIYB7w90fwMcxH24SsqLmzPyAMGfwjwIMQ863zlveYIpNKWVrZaDOa4vowwoOg2CcTW8gXtxK3dCPEgrZxGGAf-t8jhz_eLMUyBN1IhNrdYDRcNHWvQcwNG9woI8CCVOUHG1YXudbaFIgUYvrCIevRWvb2ubhQAo-z0duD0rQjxIDBeKerVGkO3J2eXDwdraSioXbIWsdIPEN1s8pIwJIS2CPAgV2kB3n3JZ5HwBQjpRL1CWKnqvdCjZk3RcALk6N2wHigI8CB-wbljNlfqElD25uZkNg6taS81YDRU2vfMqGVQ420O9AjxWQEAAAABJM43UU6MLMRrPlCUqossvu1q_knons5yylyWTgxZzWUAAAAAAP7___8CLgABAAAAAAAWABQrYt3E7OllKRCEmL3FL589l78_5wAAAAAAAAAAImog8ATiyw4ACAjxILmbcIO7ixv3pCtwUMZ1VQGKus54F9lZ8-w5ECD5ZuiICAjwIG6ynCyFTLPE7Rgk-0ZGCtBDyqNQx8YvaSZNHy8D8p8jCAjwIMX8zoD2Be1YWvcx_bexVPRmBX0hK-do8b8t9SarimQVCAjxIG6XtpqIEclLlhzcK1LVjqoPGrjjmLnyno8tcETMzECECAjwIF6mlfXOFY51JhrK4eze8zQlKV75OYZYqbtyi8BWxmAsCAjwIKKUcJmVoz-u-geiRV_-ZHdF0VEPXaEPFWf_JX_0e7G2CAjxIGMeD0Z5QWNKBcAEpHht007FFIILW6aSJ8f3CMkKNsneCAjwIBFr6Je8rkB7kwhPGbq0yRgFwZsvW9JhY5sXDRtrq0QwCAjwIAHAwXaus-yUgKICJB5mVvx8VZuJgjwnpb0qWPg1pi6DCAjxIAJhb8cefkVHTAMymdsxa-_i-tUua62LcpALQnPG7R9_CAjwIDvsFqBhPfAL6TCtXZd7gBWmMpx6iiZ-Ug0Jf_LlcstgCAjwIDJRBX6Q0Vge-ra-k1_g76yJWTEp6WWF13I3JpTnsZPJCAjwILykZCbkC9VQgl5gytPKKir6T9nTvKR6y05iWSHBTQgzCAgABYiWDXPXGQED45c78Ah-sGbmQAwfZwjwEAYqxtHnZiPZnJEGPx_JvKsI8SDXkqDg17YsZIrEz5acRx7mBXCKW5mKNgRYnw_-U2cpDgjxBGrArDrwCEfK6Mono428_wCD3-MNLvkMji4taHR0cHM6Ly9hbGljZS5idGMuY2FsZW5kYXIub3BlbnRpbWVzdGFtcHMub3JnCPAg10nyJ6Jn4kshQQQCKE0Lvj3hBC6nLRBVIzaPV4eh8VwI8CCQaAqWlxEbac_XOq1MOlf9iOKHEsxXspzbjK0vLpy8BwjwII3iRbRXUcDxrhAdkZmFlI15nySCSEZ7g922tF1Xln5DCPEgYYvZ1L4v4rPu_UqLfcHPtwSb2OH2GhPgVcVhhH6DpkQI8CDZCIoR20sC-uchP40oAmcLm9EJFV7xzwplj54AeVadXQjxILvLBjPFpCoz29m9Yf2qRnV7PI9GqxE8ozVQfk9QwCqrCPEgZXcMudvEoB_MJ8tqOW2PLTKAIeQBnE-1bfzptRc2gR8I8VkBAAAAAfXq-bmxWqOz7B5wKkwjzHGv2R4s7Y0Z76LqXWYNhmz0AAAAAAD-____Av0cAAAAAAAAFgAUl-skmdZDtn7Hnub6mF4HP2uVn7oAAAAAAAAAACJqIPAE4MsOAAgI8CBDmQsbEXc46Hu8DivhCBM1LGExa4TTM-wo7HpoCVjBTQgI8CCty5vkQtPHzzs8xqArOYhVSjgaDoG1ou3cojv5_P7wQQgI8SDQWB0kdXCTwbk-TqTt0QfRMyzDNLOtU1XXFgvGSRlW8wgI8CC2PKa_QCIBZtrXodq1GdEzppISMsMRDOnzr2gFjLKOAAgI8CCwQ_QF67bcFk_uJ2s0VCZmf5PGIjTmTCpt_qnVY5p_8AgI8SAbzyx7z-oxPMju6PvtQhzrJIQyH2ZAc9oyLuYemzbmZQgI8CC5bh7J74uUk91r8LwybHQFCNBC3PWeuwtMCCNFKWj19AgI8SAf4R2TUNPjaX_PWDUImpoITK0JoW89zaMKnD1wlEEi8AgI8SC2vNmdm7eyP5Ytl1yTzT0njliMdALl1ViKG-s3bG2zswgI8CCpbIVNz1GFVXdJk2zd82hBUoNFFemUPBt7IJdWEOciPwgI8CBtYdRQcrtX1FtCm1SxF7sx-5cO04U8KzbJh8fqBkyReAgI8CBHs2LGmX6gI-lV7yp1RrV7_tGfdiBAwnEFF6B6yXHzAQgI8CATotVmbXBMAixhZ-QKy5Q4lR0FusdA_wcIC1TbB7GmxAgIAAWIlg1z1xkBA-KXOw"],"envelope":["AE9wZW5UaW1lc3RhbXBzAABQcm9vZgC_ieLohOiSlAEIZBWhurBhe3AZL2DLIOZn51bYj2udH0PmgX8jvSxdtovwIGQdwbZs5qS1FBjlFdx8d0qiOjTLDdREPFUfrKMz1UL8CPEgDxczwY2m5K3R9V_2UTc50k74IgF86XcpZjgEZeZMJdgI8SBj9uUcerB2VAJpYVKmbKcFd9HvNRAR0CdePjLmTR-j-QjwIGXWuRsYRcICkynqfe701fubYBOG3sALQGbQKdyIBH41CPEgEEUFHZmfmEOw7iBSFkM5lY8IhR1bivbq9gSsxinBrhYI8SCEdAuprEhxQA28-Y-mxpDPnHFYrXFpW_ygfSJlChoA6gjxIDLuS2H5mkQT51okBzSqxvYOZ2DzeEjrKj1FhjpNDRblCPAgOatp97sEGfSkPectTIcXn_UGSclxLvXC9ouOsHYFkl8I8CBPLfD1TsHdjhkyZ9iTm9m5GTCSBT-7GhYUfap1vptsnQjxINBAKCf3cKChW811B6TkfdlxdONUiLQA88uJMnPer4KuCPEgytIBB3x7TFDT-XqOV-9vpqw1NKoAu0dhtsCbAMql2L0I8CCtNZgmApuKULvPC9nsMCaM05arV-F3o5FTlnJCnRvdMgjwIBGYo5Vxy-d7U5zKv5vp3Ii7hJPH_BDLCzA13c47p9q7CP_wCHbghVgOFMuNCPAQPZK2lHbTMqcCYUotzOQcmQjwIJ7ruRIs6HnufKxCpmLUgeUl0aUu0ov4_3PqcppS-bddCPEgI530vHzdwz_3o9jYQ3Wa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