Constraining New Physics Models with Isotope Shift Spectroscopy

TL;DR

This paper explores how isotope shift spectroscopy can be used to constrain new physics models, especially those involving long-range interactions, by detecting violations of King Linearity, and demonstrates its potential to set strong laboratory bounds.

Contribution

It extends the formalism for isotope shift analysis to multiple transitions and isotope pairs, enabling more comprehensive constraints on new physics models.

Findings

King Linearity Violation can strongly constrain B-L vector bosons, Higgs portal, and chameleon models.

The method can probe couplings relevant to the Be anomaly interpretation.

Current isotope shift data already provide meaningful bounds on certain new physics scenarios.

Abstract

Isotope shifts of transition frequencies in atoms constrain generic long- and intermediate-range interactions. We focus on new physics scenarios that can be most strongly constrained by King Linearity Violation such as models with B-L vector bosons, Higgs portal and chameleon. With the anticipated precision, King Linearity Violation has the potential to set the strongest laboratory bounds on these models in some regions of parameter space. Furthermore, we show that this method can probe the couplings relevant for the protophobic interpretation of the recently reported Be anomaly. We extend the formalism to include an arbitrary number of transitions and isotope pairs and fit the new physics coupling to the currently available isotope shift measurements.