Snowmass2021 CMB-HD White Paper

Kavli Affiliate: Blake Sherwin

| First 5 Authors: The CMB-HD Collaboration, :, Simone Aiola, Yashar Akrami, Kaustuv Basu

| Summary:

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.

| Search Query: ArXiv Query: search_query=au:”Blake Sherwin”&id_list=&start=0&max_results=3

Read More