Snowmass2021 CMB-HD White Paper

Abstract

CMB-HD is a proposed millimeter-wave survey over half the sky that would be ultra-deep (0.5 uK-arcmin) and have unprecedented resolution (15 arcseconds at 150 GHz). Such a survey would answer many outstanding questions about the fundamental physics of the Universe. Major advances would be 1.) the use of gravitational lensing of the primordial microwave background to map the distribution of matter on small scales (k~10 h Mpc^(-1)), which probes dark matter particle properties. It will also allow 2.) measurements of the thermal and kinetic Sunyaev-Zel'dovich effects on small scales to map the gas density and velocity, another probe of cosmic structure. In addition, CMB-HD would allow us to cross critical thresholds: 3.) ruling out or detecting any new, light (< 0.1 eV) particles that were in thermal equilibrium with known particles in the early Universe, 4.) testing a wide class of multi-field models that could explain an epoch of inflation in the early Universe, and 5.) ruling out or detecting inflationary magnetic fields. CMB-HD would also provide world-leading constraints on 6.) axion-like particles, 7.) cosmic birefringence, 8.) the sum of the neutrino masses, and 9.) the dark energy equation of state. The CMB-HD survey would be delivered in 7.5 years of observing 20,000 square degrees of sky, using two new 30-meter-class off-axis crossed Dragone telescopes to be located at Cerro Toco in the Atacama Desert. Each telescope would field 800,000 detectors (200,000 pixels), for a total of 1.6 million detectors.

arXiv commentContribution to Snowmass 2021. Note some text overlap with CMB-HD Astro2020 APC and RFI (arXiv:1906.10134, arXiv:2002.12714). Science case further broadened and updated

Cited by in corpus (17)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Gravitational Wave from Graviton Bremsstrahlung during Reheating
• Inflationary Potential as seen from Different Angles: Model Compatibility from Multiple CMB Missions
• Upper Bound on Thermal Gravitational Wave Backgrounds from Hidden Sectors
• Cosmology from the kinetic polarized Sunyaev Zel'dovich effect
• Free-Streaming Neutrinos and Their Phase Shift in Current and Future CMB Power Spectra
• Bounds on Velocity-Dependent Dark Matter-Baryon Scattering from Large-Scale Structure
• The Atacama Cosmology Telescope: DR6 Power Spectrum Foreground Model and Validation
• Misalignment production of vector boson dark matter from axion-SU(2) inflation
• Resilience and implications of adiabatic CMB cooling
• Prospects for disentangling dark matter with weak lensing
• Atacama Large Aperture Submillimeter Telescope (AtLAST) Science: Resolving the Hot and Ionized Universe through the Sunyaev-Zeldovich effect
• Using $\Delta N_{\mathrm{eff}}$ to constrain preferred axion model dark matter
• Reconstructing patchy helium reionization using the cosmic microwave background and large-scale structure
• Improving Cosmic Birefringence Constraints via Delensing
• Cosmic Strings-induced CMB anisotropies in light of Weighted Morphology
• Imprints of light dark matter on the evolution of cosmic neutrinos