SPT-3G: Measurements of CMB Lensing Power Spectrum with 2019 and 2020 Temperature and Polarization Data

Gravitational lensing of the cosmic microwave background (CMB) is an effective probe of the projected matter fluctuation integrated along the line of sight through the observable universe. Recent measurements of the CMB lensing power spectrum are providing precise and competitive cosmological parameter constraints of the standard cosmological model LCDM, informing the “S8 tension” and further constraining the sum of neutrino masses. SPT-3G is a high-resolution, high-sensitivity mm-wave camera installed on the 10-m South Pole Telescope, ideal for measurements of CMB lensing. I will present the lensing convergence map and its power spectrum derived from the 2019/2020 temperature and polarization data over the main 1500 deg^2 patch. This work employs the global minimum variance quadratic estimator paired with foreground mitigation strategies. The lensing map, which is the deepest to date, is signal-dominated out to L ~ 400, with significant contributions from polarization. We report lensing bandpowers out to L of a few thousands allowing us to probe physics towards the non-linear scales. Combining with the primary CMB power spectra measurements from the same data set, we are projected to constrain the Hubble constant at a higher precision than Planck.