The curious case of high-energy deuterons in Galactic cosmic rays

Abstract

A new analysis of cosmic ray (CR) data collected by the SOKOL experiment in space found that the deuteron-to-helium ratio at energies between 500 and 2000 GeV/nucleon takes the value d/He ~ 1.5. As we will show, this result cannot be explained by standard models of secondary CR production in the interstellar medium and points to the existence of a high-energy source of CR deuterons. To account for the deuteron excess in CRs, we argue that the only viable solution is hadronic interaction processes of accelerated particles inside old supernova remnants (SNRs). From this mechanism, however, the B/C ratio is also expected to increase at energy above ~50 of GeV/nucleon, in conflict with new precision data just released by the AMS-02 experiment. Hence, if this phenomenon is a real physical effect, hadronic production of CR deuterons must occur in SNRs characterized by low metal abundance. In such a scenario, the sources accelerating C-N-O nuclei are not the same as those accelerating helium or protons, so that the connection between d/He ratio and B/C ratio is broken, and the latter cannot be used to place constraints on the production of light isotopes or antiparticles.

5 pages, 3 figures, matches published version

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Cited by in corpus (7)

• Testing diffusion of cosmic rays in the heliosphere with proton and helium data from AMS
• Dark Matter Search in Space: Combined Analysis of Cosmic Ray Antiproton-to-Proton Flux Ratio and Positron Flux Measured by AMS-02
• Numerical modeling of cosmic-ray transport in the heliosphere and interpretation of the proton-to-helium ratio in Solar Cycle 24
• Deuteron and Antideuteron Production Simulation in Cosmic-ray Interactions
• Production and acceleration of antinuclei in supernova shockwaves
• Current status and new perspectives on cosmic ray deuterons
• Fresh Insights on Cosmic-ray Propagation from the New AMS Data