Abstract
We propose an experiment to search for QCD axion and axionlike-particle dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying -odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of an electric field. Precision magnetometry can be used to search for such precession. An initial phase of this experiment could cover many orders of magnitude in axionlike-particle parameter space beyond the current astrophysical and laboratory limits. And with established techniques, the proposed experimental scheme has sensitivity to QCD axion masses , corresponding to theoretically well-motivated axion decay constants . With further improvements, this experiment could ultimately cover the entire range of masses , complementary to cavity searches.
- Received 9 July 2013
DOI:https://doi.org/10.1103/PhysRevX.4.021030
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Published by the American Physical Society
Popular Summary
The nature of dark-matter particles is one of the most fundamental open problems in physics since dark matter constitutes over 85% of the total matter in the Universe. The currently unknown particle likely experiences nongravitational interactions; observing such interactions would uncover new laws of nature and reveal the origins of the dominant source of matter in the cosmos. Ultralight bosons such as axions and axionlike particles are prime dark-matter candidates since weakly interacting massive particles as dark-matter particles have been strongly constrained by previous studies. Axionlike particles can manifest themselves as an energy density in the form of oscillations of a background field; the oscillations occur at specific frequencies set by particle physics in the kHz–GHz range and are accessible in the laboratory. We propose new techniques based on precision magnetometry to sensitively search for such particles with masses as low as 10–12 eV, a wide range of parameter space that has hitherto been unexplored.
We advocate using nuclear-magnetic-resonance techniques to investigate axionlike dark-matter particles. The fields associated with these particles can cause the precession of nucleon spins, changing the magnetization of a sample of polarized nuclear spins. Such an effect can be detected using precision magnetometry; the nucleon spin precessions can be resonantly enhanced and detected using nuclear-magnetic-resonance techniques.
With current technology, this technique appears to have the sensitivity to probe axionlike dark-matter particles if the particles emerge from energy scales associated with grand unified theories and quantum gravity. A signal in these experiments can be unambiguously verified using several detectors since the frequency of the dark-matter signal is independent of the experimental setup.