WMAP 5-year constraints on time variation of $\alpha$ and $m_e$

TL;DR

This paper uses WMAP 5-year and 2dFGRS data to constrain the possible time variation of the fine structure constant and electron mass during the early Universe, providing bounds on their changes.

Contribution

It presents updated bounds on the time variation of lpha and m_e using CMB and galaxy survey data, considering scenarios where both or only one constant varies.

Findings

lpha variation constrained to -0.019 to 0.017 at 95% confidence

Constraints depend on the recombination scenario used

Joint estimation of lpha and cosmological parameters achieved

Abstract

We studied the role of fundamental constants in an updated recombination scenario, focusing on the time variation of the fine structure constant \alpha and the electron mass m_e in the early Universe. Using CMB data including WMAP 5-yr release, and the 2dFGRS power spectrum, we put bounds on variations of these constants, when both constants are allowed to vary, and in the case that only one of them is variable. In particular, we have found that -0.019 < \Delta \alpha / \alpha_0 < 0.017 (95% c.l.), in our joint estimation of \alpha and cosmological parameters. Finally, we analyze how the constraints depends on the recombination scenario.