Sensitivity of Next-Generation CMB Surveys to Neutrinos and Other Light Relics

arXiv:2608.07453 · astro-ph.CO, astro-ph.IM, hep-ph, hep-th · Submitted 2026-08-07 · Read on arXiv

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astro-ph.CO, astro-ph.IM, hep-ph, hep-th

Submitted: 2026-08-07

Updated: 2026-08-07

Comments: 76 pages, 8 figures, 8 tables; DRAFT forecasting tool available at https://github.com/sriniraghunathan/DRAFT

Code: https://github.com/sriniraghunathan/DRAFT

License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Terminology

• Abundance — 36× in this paper · explained in 1 episode
• Decoupling — 33× in this paper · explained in 2 episodes
• Reheating — 21× in this paper · explained in 2 episodes
• Simons Observatory — 14× in this paper
• Aperture — 11× in this paper · explained in 1 episode
• Degeneracy — 11× in this paper · explained in 3 episodes
• Anisotropy — 8× in this paper · explained in 3 episodes
• Consistency — 6× in this paper · explained in 3 episodes
• Fisher Information — 6× in this paper · explained in 3 episodes
• Phase Transitions — 6× in this paper · explained in 2 episodes
• South Pole Telescope — 6× in this paper
• Benchmark — 5× in this paper · explained in 2 episodes
• Spectral Distortions — 5× in this paper · explained in 2 episodes
• Fidelity — 4× in this paper · explained in 2 episodes
• Gravitational Lensing — 4× in this paper · explained in 2 episodes
• Symmetry Breaking — 4× in this paper · explained in 3 episodes
• US Department of Energy — 4× in this paper
• Adam — 3× in this paper · explained in 2 episodes
• Clustering — 3× in this paper · explained in 2 episodes
• Hubble Tension — 3× in this paper · explained in 9 episodes
• Matter Power Spectrum — 3× in this paper · explained in 2 episodes
• Dark Radiation Anisotropy Flowdown Team — 2× in this paper
• Frequency Dependence — 2× in this paper · explained in 2 episodes
• National Center for Supercomputing Applications — 2× in this paper
• Probe of Inflation and Cosmic Origins — 2× in this paper
• Baryonic Feedback — 1× in this paper · explained in 3 episodes
• Bispectrum — 1× in this paper · explained in 3 episodes
• Core — 1× in this paper · explained in 2 episodes
• Cosmic Linear Anisotropy Solving System — 1× in this paper
• Generalization — 1× in this paper · explained in 13 episodes
• Model-Agnostic — 1× in this paper · explained in 2 episodes
• National Energy Research Scientific Computing Center — 1× in this paper
• National Science Foundation — 1× in this paper
• National Supercomputer Centre — 1× in this paper
• Packed Ultra-wideband Mapping Array — 1× in this paper
• Systematic Bias — 1× in this paper · explained in 3 episodes
• Weak Lensing — 1× in this paper · explained in 2 episodes

Sources

• Snowmass Theory Frontier: Astrophysics and Cosmology
• Report of the Topical Group on Cosmic Frontier 5 Dark Energy and Cosmic Acceleration: Cosmic Dawn and Before for Snowmass 2021
• TASI Lectures on Cosmic Signals of Fundamental Physics
• Messengers from the Early Universe: Cosmic Neutrinos and Other Light Relics
• Synergy between cosmological and laboratory searches in neutrino physics
• The Physics of Light Relics
• Prospects and Limitations for Constraining Light Relics with Primordial Abundance Measurements
• Primordial Deuterium after LUNA: concordances and error budget
• The Impact of New d(p,\gamma)He3 Rates on Big Bang Nucleosynthesis
• EMPRESS. VIII. A New Determination of Primordial He Abundance with Extremely Metal-Poor Galaxies: A Suggestion of the Lepton Asymmetry and Implications for the Hubble Tension
• Probing Physics Beyond the Standard Model: Limits from BBN and the CMB Independently and Combined
• EMPRESS. XV. A New Determination of the Primordial Helium Abundance Suggesting a Moderately Low $Y_\mathrm{P}$ Value
• The LBT $Y_{\rm p}$ Project V: Cosmological Implications of a New Determination of Primordial $^4$He
• Precision big bang nucleosynthesis with improved Helium-4 predictions
• Big Bang Nucleosynthesis and Neutrino Cosmology
• Big-Bang Nucleosynthesis After Planck
• Big Bang Nucleosynthesis
• Big Bang Nucleosynthesis
• Searching for Light Relics with Large-Scale Structure
• Cosmology in the era of Euclid and the Square Kilometre Array

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