2024/02/23 by Michael A. Fedderke, David E. Kaplan, Anubhav Mathur +2 · 1 voice · 2 citations
Pharmacology, Toxicology and Pharmaceutics · Physics and Astronomy · #Chemical Reactions and Isotopes #astro-ph.CO #astro-ph.GA #astro-ph.HE #hep-ph
paper · pdf · doi:10.1103/physrevd.109.123028
arxiv published 2024/02/23 · arxiv updated 2024/06/18 · openalex publication_date 2024/06/21 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The tentative identification of approximately ten relativistic antihelium ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mover accent="true"> <a:mi>He</a:mi> <a:mo stretchy="true">¯</a:mo> </a:mover> </a:math> ) cosmic-ray events at AMS-02 would, if confirmed, challenge our understanding of the astrophysical synthesis of heavy antinuclei. We propose a novel scenario for the enhanced production of such antinuclei that is triggered by isolated, catastrophic injections of large quantities of energetic Standard Model (SM) antiquarks in our galaxy by physics beyond the Standard Model (BSM). We demonstrate that SM antinucleosynthetic processes that occur in the resulting rapidly expanding, thermalized fireballs of SM plasma can, for a reasonable range of parameters, produce the reported tentative <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mo>∼</e:mo> <e:mn>2</e:mn> <e:mo>:</e:mo> <e:mn>1</e:mn> </e:math> ratio of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"> <g:mrow> <g:mmultiscripts> <g:mrow> <g:mover accent="true"> <g:mrow> <g:mi>He</g:mi> </g:mrow> <g:mrow> <g:mo stretchy="true">¯</g:mo> </g:mrow> </g:mover> </g:mrow> <g:mprescripts/> <g:none/> <g:mn>3</g:mn> </g:mmultiscripts> </g:mrow> </g:math> to <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:mrow> <k:mmultiscripts> <k:mrow> <k:mover accent="true"> <k:mrow> <k:mi>He</k:mi> </k:mrow> <k:mrow> <k:mo stretchy="true">¯</k:mo> </k:mrow> </k:mover> </k:mrow> <k:mprescripts/> <k:none/> <k:mn>4</k:mn> </k:mmultiscripts> </k:mrow> </k:math> events at AMS-02, as well as their relativistic boosts. Moreover, we show that this can be achieved without violating antideuterium or antiproton flux constraints for the appropriate antihelium fluxes. A plausible BSM paradigm for the catastrophic injections is the collision of macroscopic composite dark-matter objects carrying large net antibaryon number. Such a scenario would require these objects to be cosmologically stable, but to destabilize upon collision, promptly releasing a fraction of their mass energy into SM antiparticles within a tiny volume. We show that, in principle, the injection rate needed to attain the necessary antihelium fluxes and the energetic conditions required to seed the fireballs appear possible to obtain in such a paradigm. We leave open the question of constructing a BSM particle physics model to realize this, but we suggest two concrete scenarios as promising targets for further investigation. Published by the American Physical Society 2024