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Dark Matter, Baryon Number, and Cosmic-Ray Antinuclei

Caleb Gemmell1,*, Dan Hooper1,†, Seth Koren2,‡, and Fabrizio Vassallo1,§

  • *Contact author: cgemmell2@wisc.edu
  • †Contact author: dwhooper@wisc.edu
  • ‡Contact author: skoren@nd.edu
  • §Contact author: fevassallo@wisc.edu
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Phys. Rev. Lett. 137, 171802 – Published 22 October, 2026

DOI: https://doi.org/10.1103/6rsq-mjzw

Abstract

Antideuterons and antihelium nuclei in the cosmic-ray spectrum have long been considered a smoking gun signature of dark matter annihilation, making the tentative observation of several such events by AMS highly intriguing. Conventional dark matter models, however, can produce only up to O(1) antideuteron events at AMS and are not capable of generating observable fluxes of antihelium. In this Letter, we propose a class of models in which dark matter annihilates into particles carrying baryon and lepton number, whose subsequent decays produce enhanced fluxes of antinucleons and antinuclei. Such scenarios are motivated by grand unified theories and can lead to an order-of-magnitude or larger enhancement in the resulting antideuteron and antihelium-3 fluxes, providing a means by which to potentially explain the events reported by the AMS Collaboration.

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Phys. Rev. Lett. 137, 171802– Published 22 October, 2026
  • Received 13 April 2026
  • Revised 10 July 2026
  • Accepted 29 September 2026
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