Deuterium spectroscopy for enhanced bounds on physics beyond the Standard Model

TL;DR

Combining precision spectroscopy of hydrogen and deuterium significantly improves bounds on hypothetical light bosons beyond the Standard Model, especially if the interaction differs between proton and deuteron.

Contribution

This work demonstrates that using isotope comparisons enhances sensitivity to new physics, surpassing single-isotope methods, and suggests extending measurements for even greater bounds.

Findings

Bounds on light-mass bosons are orders of magnitude more sensitive with isotope data.

Differential coupling to deuteron and proton enhances detection sensitivity.

Extending isotope shift measurements could improve bounds by an order of magnitude.

Abstract

We consider the impact of combining precision spectroscopic measurements made in atomic hydrogen with similar measurements made in atomic deuterium on the search for physics beyond the Standard Model. Specifically we consider the wide class of models that can be described by an effective Yukawa-type interaction between the nucleus and the electron. We find that it is possible to set bounds on new light-mass bosons that are orders of magnitude more sensitive than those set using a single isotope only, provided the interaction couples differently to the deuteron and proton. Further enhancements of these bounds by an order of magnitude or more would be made possible by extending the current measurements of the isotope shift of the 1s$_{1/2}$-2s$_{1/2}$ transition frequency to that of a transition between the 2s$_{1/2}$ state and a Rydberg s-state.