# Cosmology From CMB Lensing and Delensed EE Power Spectra Using 2019-2020 SPT-3G Polarization Data

**Authors:** F. Ge, M. Millea, E. Camphuis, C. Daley, N. Huang, Y. Omori, W. Quan, E. Anderes, A. J. Anderson, B. Ansarinejad, M. Archipley, L. Balkenhol, K. Benabed, A. N. Bender, B. A. Benson, F. Bianchini, L. E. Bleem, F. R. Bouchet, L. Bryant, J. E. Carlstrom  
**arXiv:** [2411.06000](https://arxiv.org/abs/2411.06000)  
**Date:** 2024-11-08  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2411.06000v1/

## Key points

- Researchers utilized CMB polarization data to reconstruct the CMB lensing power spectrum and the unlensed E-mode power spectrum
- Observations were conducted in 2019 and 2020 using the South Pole Telescope (SPT) and SPT-3G camera
- Data covered 1500 deg$^2$ at frequencies of 95, 150, and 220 GHz with high arcminute resolution
- Precise estimates of the E-mode spectrum at $\ell>2000$ and the lensing spectrum at $L>350$ were obtained through Bayesian analysis using the MUSE method
- Determined a value of $H_0=66.81\pm0.81$ km/s/Mpc from SPT data alone, showing a significant tension with measurements from the distance ladder
- Found $S_8=0.850\pm0.017$, indicating further evidence of a discrepancy with low-redshift structure probes
- Confirmed that the $\Lambda$CDM model provided an excellent fit to combined datasets from Planck, ACT, and SPT
- Established a 95% confidence upper limit on the sum of neutrino masses at 0.075 eV

## Summary

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In a recent study, researchers utilized CMB polarization data to reconstruct the CMB lensing power spectrum and the unlensed E-mode power spectrum. The observations were conducted in 2019 and 2020 using the South Pole Telescope (SPT) and the SPT-3G camera, covering 1500 deg$^2$ at frequencies of 95, 150, and 220 GHz with high arcminute resolution. The data had a coadded noise level of approximately 4.9$\mu$K-arcmin in polarization. Through a Bayesian analysis employing the Marginal Unbiased Score Expansion (MUSE) method, the researchers obtained precise estimates of the E-mode spectrum at $\ell>2000$ and the lensing spectrum at $L>350$, currently among the most accurate to date. In a recent study, researchers utilized CMB polarization data to reconstruct the CMB lensing power spectrum and the unlensed E-mode power spectrum. Researchers used CMB polarization data to reconstruct this spectrum with high precision. Assuming the $\Lambda$CDM model and incorporating priors on parameters such as $\tau$ and absolute calibration from Planck, they determined a value of $H_0=66.81\pm0.81$ km/s/Mpc from the SPT data alone. This result is comparable in precision to previous determinations by Planck but shows a significant tension of 5.4$\sigma$ with measurements derived from the distance ladder. A Bayesian analysis using this method provided precise estimates of the E-mode and lensing spectra. The researchers found a significant tension of 5.4$\sigma$ between their determination of $H_0$ and measurements from the distance ladder. Additionally, they found $S_8=0.850\pm0.017$, indicating further evidence of a slight discrepancy with low-redshift structure probes. The researchers confirmed that the $\Lambda$CDM model provided an excellent fit to combined datasets from Planck, ACT, and SPT, passing rigorous testing criteria. By combining their CMB datasets with observations from Baryon Acoustic Oscillations (BAO), they determined that parameters such as effective number of neutrino species, spatial curvature, primordial helium fraction were consistent with standard model values. Moreover, they established a 95% confidence upper limit on the sum of neutrino masses at 0.075 eV. The study detected these effects in the CMB lensing power spectrum at greater than 3$\sigma$, shedding light on discrepancies related to $S_8$. Overall, these findings contribute valuable insights into cosmological models and highlight areas where further investigation is warranted for resolving tensions within current observational constraints.