Princeton University Gravity Group Lunch Seminar

Measurements of the small-scale CMB temperature and polarization fields have recently undergone transformative improvements with Data Release 6 (DR6) of the Atacama Cosmology Telescope (ACT) and will soon improve further with the Simons Observatory (SO), which will open new windows into physics beyond the standard models (BSM) of particle physics and cosmology. I will very briefly highlight key findings from our ACT DR6 CMB power spectrum analysis, particularly pertaining to beyond-LCDM models motivated by the "Hubble tension." I will then discuss signals of BSM physics in CMB secondary anisotropies, as could be imprinted by the conversion of CMB photons into massive dark photons (DPs) or axion-like particles. I will show the first results of searches for these signals in CMB data, enabled by our state-of-the-art needlet internal linear combination (NILC) code, yielding leading bounds on DP-photon and axion-photon couplings over two decades in DP/axion mass. I will then present a new NILC-based B-mode inference method, which yields unbiased constraints on the tensor-to-scalar ratio at SO sensitivity and beyond, even for the most complex foreground simulations currently available. Finally, if time permits, I will present robust evidence of a new (standard-model) secondary anisotropy in the microwave sky, arising from the kinematic SZ effect.