Earth-bound millicharge relics

Maxim Pospelov, Harikrishnan Ramani

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17 Scopus citations


Dark sector particles with small electric charge, or millicharge, (mCPs) may lead to a variety of diverse phenomena in particle physics, astrophysics, and cosmology. Assuming their possible existence, we investigate the accumulation and propagation of mCPs in matter, specifically inside the Earth. Even small values of millicharge lead to sizeable scattering cross sections on atoms, resulting in complete thermalization, and as a consequence, considerable build-up of number densities of mCPs, especially for the values of masses of GeV and higher when the evaporation becomes inhibited. Enhancement of mCP densities compared to their galactic abundance, that can be as big as 1014, leads to the possibility of new experimental probes for this model. The annihilation of pairs of mCPs will result in new signatures for the large volume detectors (such as Super-Kamiokande). Formation of bound states of negatively charged mCPs with nuclei can be observed by direct dark matter detection experiments. A unique probe of mCP can be developed using underground electrostatic accelerators that can directly accelerate mCPs above the experimental thresholds of direct dark matter detection experiments.

Original languageEnglish (US)
Article number115031
JournalPhysical Review D
Issue number11
StatePublished - Jun 25 2021

Bibliographical note

Funding Information:
We are indebted to Dr. A. Berlin and Dr. H. Liu for valuable critical comments. We are also grateful to Dr. R. Harnik and Dr. R. Plestid for earlier collaboration on the mCP project. M. P. would like to thank Dr. T. Bringmann for earlier discussions of related ideas. M. P. is supported in part by U.S. Department of Energy (Grant No. desc0011842).

Publisher Copyright:
© 2021 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the ""Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.


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