Median Statistics Analysis of Deuterium Abundance Measurements and Spatial Curvature Constraints

TL;DR

This paper uses median statistics to analyze deuterium abundance measurements, providing a robust estimate of baryon density that aligns with Planck 2015 data in flat models but suggests lower values in closed models.

Contribution

It introduces median statistics as a more accurate method for combining deuterium measurements and compares the results with Planck 2015 cosmological data.

Findings

Median statistic estimate aligns with flat Planck data

Estimate is about 2sigma lower in closed cosmological models

Median approach reduces bias from outliers or non-Gaussian data

Abstract

Zavarygin et al. (2018) compiled a list of 15 deuterium abundance measurements, discarded two because the remaining 13 measurements are then consistent with gaussianity, and found that the weighted mean baryon density (Omega_b h^2) determined from the 13 measurements is mildly discrepant (1.6sigma) with that determined from the Planck 2015 cosmic microwave background anisotropy data in a flat cosmogony. We find that a median statistic central estimate of Omega_b h^2 from all 15 deuterium abundance measurements is a more accurate estimate, is very consistent with Omega_b h^2 estimated from Planck 2015 data in a flat cosmogony, but is about 2sigma lower than that found in a closed cosmogonical model from the Planck 2015 data.