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Probing New Hadronic Forces with Heavy Exotic Atoms

Hongkai Liu1,2,*, Ben Ohayon1,†, Omer Shtaif1,‡, and Yotam Soreq1,§

  • *Contact author: hliu6@bnl.gov
  • †Contact author: bohayon@technion.ac.il
  • ‡Contact author: omer.shtaif@campus.technion.ac.il
  • §Contact author: soreqy@physics.technion.ac.il
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Phys. Rev. Lett. 135, 131803 – Published 26 September, 2025

DOI: https://doi.org/10.1103/ndfg-42w7

Abstract

We explore the potential of precision spectroscopy of heavy exotic atoms where electrons are substituted by negative hadrons to detect new force carriers with hadronic couplings. The selected transitions are unaffected by nuclear contact terms, thus enabling highly accurate calculations using bound-state QED, provided that the nuclear polarization is under control. Alternatively, we demonstrate that the dipole polarizability, a fundamental property of nuclei, can be extracted from the spectroscopy of exotic atoms in a novel way by combining two transitions while maintaining high sensitivity to new physics. Based on existing data, we extracted world-leading bounds on mediator masses ranging from 0.1 to 10 MeV for two benchmark models and show that forthcoming experiments could enhance the sensitivity to new physics by 2 orders of magnitude.

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Phys. Rev. Lett. 135, 131803– Published 26 September, 2025
  • Received 24 February 2025
  • Revised 7 July 2025
  • Accepted 5 September 2025
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