Comment on "Clock Shift in High Field Magnetic Resonance of Atomic Hydrogen"

TL;DR

This paper reanalyzes atomic hydrogen experiments to correct a previous error, accurately determining the difference in scattering lengths and clarifying the collision frequency shift in hyperfine transitions.

Contribution

It provides a corrected analysis of hydrogen collision shifts, accurately calculating the scattering length difference and addressing prior inaccuracies.

Findings

Corrected the scattering length difference to 0.30(5) Å.

Identified and fixed a factor-of-two error in previous work.

Refined understanding of hyperfine transition shifts in atomic hydrogen.

Abstract

In this Comment, we reanalyze the experiments on the collision frequency shift of the b-c and a-d hyperfine transitions in three-dimensional atomic hydrogen in the presence of, respectively, a and b-state atoms. Accurate consideration of the symmetry of the spatial and spin part of the diatomic wavefunction yields the difference a_T-a_S=0.30(5) \AA between the triplet and singlet s-wave scattering lengths of hydrogen atoms. This corrects the factor-of two error of the commented work [Phys. Rev. Lett. 101, 263003 (2008)].