Electric fields probe the symmetry of the ‘heavy hydrogen’ nucleus

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25 June 2026 Electric fields probe the symmetry of the ‘heavy hydrogen’ nucleus The response of the nucleus of a deuterium atom to electric fields shows no evidence of asymmetry, which is consistent with conventional theories of particle physics. By Steven Hoekstra 0 Steven Hoekstra Steven Hoekstra is in the Van Swinderen Institute for Particle Physics and Gravity, University of Groningen, Groningen 9747 AG, The Netherlands, and Nikhef, National Institute for Subatomic Physics, Amsterdam 1098 XG, The Netherlands. View author publications PubMed Google Scholar

When the needle of a compass interacts with Earth’s magnetic field, it experiences a rotational force that, in most locations, aligns it with magnetic north. This force depends on a property of the needle called the magnetic dipole moment. Objects that have a preferred orientation in electric fields have an electric dipole moment (EDM). According to conventional theory, the EDMs of atomic nuclei are effectively zero — a non-zero value could be explained only by new fundamental theories of matter. Writing in Physical Review Letters, Andres et al.1 report the first direct measurement of the EDM of an atomic nucleus called a deuteron. The results, which were obtained at the Cooler Synchrotron (COSY) experiment in Jülich, Germany, are consistent with a deuteron having an EDM of zero.

doi: https://doi.org/10.1038/d41586-026-02036-z

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Competing Interests The author declares no competing interests.

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