Mass Calibration of DES Year-3 Clusters Via SPT-3G CMB Cluster Lensing

We measure the stacked lensing signal in the direction of galaxy clusters inthe Dark Energy Survey Year 3 (DES Y3) redMaPPer sample, using cosmic microwavebackground (CMB) temperature data from SPT-3G, the third-generation CMB cameraon the South Pole Telescope (SPT). We estimate the lensing signal usingtemperature maps constructed from the initial 2 years of data from the SPT-3G'Main' survey, covering 1500 deg^2 of the Southern sky. We then use thissignal as a proxy for the mean cluster mass of the DES sample. In this work, weemploy three versions of the redMaPPer catalogue: a Flux-Limited samplecontaining 8865 clusters, a Volume-Limited sample with 5391 clusters, and aVolume Redshift-Limited sample with 4450 clusters. For the three samples, wefind the mean cluster masses to be M_200m=1.66±0.13[stat.]±0.03 [sys.], 1.97±0.18 [stat.]±0.05 [sys.], and2.11±0.20 [stat.]±0.05 [sys.]×10^14 M_⊙,respectively. This is a factor of ∼2 improvement relative to the precisionof measurements with previous generations of SPT surveys and the mostconstraining cluster mass measurements using CMB cluster lensing to date.Overall, we find no significant tensions between our results and masses givenby redMaPPer mass-richness scaling relations of previous works, which werecalibrated using CMB cluster lensing, optical weak lensing, and velocitydispersion measurements from various combinations of DES, SDSS and Planck data.We then divide our sample into 3 redshift and 3 richness bins, finding nosignificant tensions with optical weak-lensing calibrated masses in these bins.We forecast a 5.8% constraint on the mean cluster mass of the DES Y3 samplewith the complete SPT-3G surveys when using both temperature and polarizationdata and including an additional ∼1400 deg^2 of observations from the'Extended' SPT-3G survey.