Unitarity in the non-relativistic regime and implications for dark matter

Abstract

Unitarity sets upper limits on partial-wave elastic and inelastic cross-sections, which are often violated by perturbative computations. We discuss the dynamics underlying these limits in the non-relativistic regime, namely long-range interactions, and show how the resummation of the 2-particle-irreducible diagrams arising from squaring inelastic processes unitarizes both elastic and inelastic cross-sections. We provide a simple prescription to obtain the unitarized cross-sections from those that do not include resummation of the squared inelastic processes. Our results are model-independent, apply to all partial waves, and affect elastic and inelastic cross-sections, with extensive implications for new physics scenarios, such as dark-matter freeze-out, indirect detection and self-interactions.

12 pages, 4 figures; v2. discussion expanded, published version

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Cited by in corpus (4)

• t-channel dark matter at the LHC -- a whitepaper
• The role of unitarisation on dark-matter freeze-out via metastable bound states
• Unitarity violation and restoration in radiative bound-state formation
• BSFfast: Rapid computation of bound-state effects on annihilation in the early Universe