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| Format: | Recurso digital |
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Zenodo
2026
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| Online Access: | https://doi.org/10.5281/zenodo.19413818 |
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Table of Contents:
- <p><span><span>The U-Cell Model (UCM) predicts </span><span><span><span><span><span><span>Ω</span><span><span><span><span><span><span><span><span>m</span></span></span></span></span><span><span></span></span></span></span></span></span><span><span>=</span></span></span><span><span><span>0.3166</span></span></span></span></span></span><span> and </span><span><span><span><span><span><span>w</span></span><span><span>=</span></span></span><span><span><span>−</span></span><span><span>1</span></span></span></span></span></span><span> exactly from </span><span><span><span><span><span><span><span>f</span></span><span><span><span><span><span><span><span><span><span>co</span></span><span><span>l</span></span><span><span>d</span></span></span></span></span></span><span><span></span></span></span></span></span></span><span><span>=</span></span></span><span><span><span><span><span><span><span><span><span>2</span></span><span><span>−</span></span><span><span>π</span></span><span><span>/2</span></span></span></span></span><span><span></span></span></span></span></span></span></span></span></span><span>, with zero free parameters</span></span><span><span><sup></sup><sup></sup><sup></sup></span></span><span>. </span><span><span>This paper tests these predictions against the Union3 compilation of 2087 Type Ia supernovae (Rubin et al. 2024), the largest current SN Ia sample, analysed with the UNITY1.5 Bayesian framework and SALT3 light-curve fitting</span></span><span><span><sup></sup></span></span><span>. </span><span><span>The Union3 SN-only constraint (</span><span><span><span><span><span><span>w</span></span><span><span>=</span></span></span><span><span><span>−</span></span><span><span>1</span></span></span></span></span></span><span>, flat prior) gives </span><span><span><span><span><span><span>Ω</span><span><span><span><span><span><span><span><span>m</span></span></span></span></span><span><span></span></span></span></span></span></span><span><span>=</span></span></span><span><span><span>0.31</span></span><span><span>5</span><span><span><span><span><span><span><span><span>−</span><span>0.033</span></span></span></span><span><span><span><span>+</span><span>0.028</span></span></span></span></span><span><span></span></span></span></span></span></span></span></span></span></span><span>, consistent with the UCM prediction at </span><span><span><span><span><span><span>0.05</span></span><span><span>σ</span></span></span></span></span></span></span><span><span><sup></sup></span></span><span>. </span><span><span>The spline-node </span><span><span><span><span><span><span><span>χ</span></span><span><span><span><span><span><span><span><span>2</span></span></span></span></span></span></span></span></span></span></span></span></span><span> analysis gives </span><span><span><span><span><span><span><span>χ</span></span><span><span><span><span><span><span><span><span>2</span></span></span></span></span></span></span></span></span><span><span>/</span></span><span><span>d</span></span><span><span>o</span></span><span><span>f</span></span><span><span>=</span></span></span><span><span><span>1.090</span></span></span></span></span></span><span> with </span><span><span><span><span><span><span>Δ</span></span><span><span>B</span></span><span><span>I</span></span><span><span>C</span></span><span><span>=</span></span></span><span><span><span>+</span></span><span><span>7.8</span></span></span></span></span></span><span> in favour of the UCM</span></span><span><span><sup></sup></span></span><span>. </span><span><span>The reported </span><span><span><span><span><span><span>1.7</span></span></span></span></span></span><span>–</span><span><span><span><span><span><span>2.6</span></span><span><span>σ</span></span></span></span></span></span><span> tension with flat </span><span><span><span><span><span><span>Λ</span></span></span></span></span></span><span>CDM in the </span><span><span><span><span><span><span><span>w</span></span><span><span><span><span><span><span><span><span>0</span></span></span></span></span><span><span></span></span></span></span></span></span></span></span></span></span><span>–</span><span><span><span><span><span><span><span>w</span></span><span><span><span><span><span><span><span><span>a</span></span></span></span></span><span><span></span></span></span></span></span></span></span></span></span></span><span> plane is present across all three independent SN compilations (Pantheon+, DES SN5YR, Union3) simultaneously, indicating a systematic rather than a physical origin</span></span><span><span><sup></sup></span></span><span>. </span><span><span>Combined with Pantheon+ (</span><span><span><span><span><span><span>Δ</span></span><span><span>B</span></span><span><span>I</span></span><span><span>C</span></span><span><span>=</span></span></span><span><span><span>+</span></span><span><span>3.0</span></span></span></span></span></span><span>) and DES SN5YR (</span><span><span><span><span><span><span>+</span></span><span><span>7.5</span></span></span></span></span></span><span>), the three SN compilations yield a combined </span><span><span><span><span><span><span>Δ</span></span><span><span>B</span></span><span><span>I</span></span><span><span>C</span></span><span><span>=</span></span></span><span><span><span>+</span></span><span><span>18.3</span></span></span></span></span></span></span><span><span><sup></sup></span></span><span>. </span><span><span>Part of the UCM preprint series (ORCID 0009-0005-5088-4339)</span></span><span><span><sup></sup></span></span><span>.</span></p>