We analyze simulated maps of the Cosmology Large Angular Scale Surveyor (CLASS) experiment and recover a nearly cosmic-variance limited estimate of the reionization optical depth τ. We use a power spectrum-based likelihood to simultaneously clean foregrounds and estimate cosmological parameters in multipole space. Using software specifically designed to constrain τ, the amplitude of scalar fluctuations As, and the tensor-to-scalar ratio r, we demonstrate that the CLASS experiment will be able to estimate τ within a factor of two of the full-sky cosmic variance limit allowed by cosmic microwave background polarization measurements. Additionally, we discuss the role of CLASS's τ constraint in conjunction with gravitational lensing of the CMB on obtaining a ≳4σ measurement of the sum of the neutrino masses.
@article{arxiv.1801.01481,
title = {A Projected Estimate of the Reionization Optical Depth Using the CLASS Experiment's Sample-Variance Limited E-Mode Measurement},
author = {Duncan J. Watts and Bingjie Wang and Aamir Ali and John W. Appel and Charles L. Bennett and David T. Chuss and Sumit Dahal and Joseph R. Eimer and Thomas Essinger-Hileman and Kathleen Harrington and Gary Hinshaw and Jeffrey Iuliano and Tobias A. Marriage and Nathan J. Miller and Ivan L. Padilla and Lucas Parker and Matthew Petroff and Karwan Rostem and Edward J. Wollack and Zhilei Xu},
journal= {arXiv preprint arXiv:1801.01481},
year = {2018}
}