Dark-matter bound states from Feynman diagrams

Abstract

If dark matter couples directly to a light force mediator, then it may form bound states in the early universe and in the non-relativistic environment of haloes today. In this work, we establish a field-theoretic framework for the computation of bound-state formation cross-sections, de-excitation and decay rates, in theories with long-range interactions. Using this formalism, we carry out specific computations for scalar particles interacting either via a light scalar or vector mediator. At low relative velocities of the interacting particles, the formation of bound states is enhanced by the Sommerfeld effect. For particle-antiparticle pairs, we show that bound-state formation can be faster than annihilation into radiation in the regime where the Sommerfeld effect is important. The field-theoretic formalism outlined here can be generalised to compute bound-state formation cross-sections in a variety of theories, including theories featuring non-Abelian (albeit non-confining) interactions, such as the electroweak interactions.

36 pages + appendices + references, 9 figures, 1 table; v2: published version

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Cited by in corpus (14)

• Effects of QCD bound states on dark matter relic abundance
• On thermal corrections to near-threshold annihilation
• Re-derived overclosure bound for the inert doublet model
• Higgs-mediated bound states in dark-matter models
• Zero-Range Effective Field Theory for Resonant Wino Dark Matter I. Framework
• Dark matter bound state formation via emission of a charged scalar
• Exotic Dark Matter Search with CDEX-10 Experiment at China's Jinping Underground Laboratory
• Strong electroweak phase transition in $t$-channel simplified dark matter models
• Gravitational Atoms
• Non-relativistic and potential non-relativistic effective field theories for scalar mediators
• Bound-state formation, dissociation and decays of darkonium with potential non-relativistic Yukawa theory for scalar and pseudoscalar mediators
• A balance for Dark Matter bound states
• Bound States of Right-handed Sneutrino Dark Matter
• Effective Field Theories for Dark Matter Pairs in the Early Universe