Testing Electron Boost Invariance with 2S-1S Hydrogen Spectroscopy

TL;DR

This study uses precise hydrogen spectroscopy measurements to test boost invariance for electrons, providing significantly improved laboratory bounds on potential violations of this fundamental symmetry.

Contribution

It demonstrates that existing 2S-1S hydrogen transition data can be used to set new, stringent limits on boost invariance violation for electrons, with potential for further improvements.

Findings

Established a new bound on boost invariance violation parameter at 4 +/- 8 x 10^(-11)

Improved laboratory bounds by eight orders of magnitude compared to previous tests

Indicated that additional measurements could yield even tighter constraints.

Abstract

There are few good direct laboratory tests of boost invariance for electrons, because the experiments required often involve repeated precision measurements performed at different times of year. However, existing measurements and remeasurements of the 2S-1S two-photon transition frequency in H--which were done to search for a time variation in the fine structure constant--also constitute a measurement of the boost symmetry violation parameter 0.83c_(TX) + 0.51c_(TY) + 0.22c_(TZ) = (4 +/- 8) x 10^(-11). This is an eight order of magnitude improvement over preexisting laboratory bounds, and with only one additional measurements, this system could yield a second comparable constraint.