Freeze-in produced dark matter in the ultra-relativistic regime

Abstract

When dark matter particles only feebly interact with plasma constituents in the early universe, they never reach thermal equilibrium. As opposed to the freeze-out mechanism, where the dark matter abundance is determined at $T\ll M$, the energy density of a feebly interacting state builds up and increases over $T\gtrsim M$. In this work, we address the impact of the high-temperature regime on the dark matter production rate, where the dark and Standard Model particles are ultra-relativistic and nearly light-like. In this setting, multiple soft scatterings, as well as $2\to 2$ processes, are found to give a large contribution to the production rate. Within the model we consider in this work, namely a Majorana fermion dark matter of mass $M$ accompanied by a heavier scalar $-$ with mass splitting $\Delta M$ $-$ which shares interactions with the visible sector, the energy density can be dramatically underestimated when neglecting the high-temperature dynamics. We find that the overall effective $1\leftrightarrow 2$ and $2\to 2$ high-temperature contributions to dark-matter production give $\mathcal{O}(10)$ (20\%) corrections for $\Delta M/M=0.1$ ($\Delta M/M=10$) to the Born production rate with in-vacuum masses and matrix elements. We also assess the impact of bound-state effects on the late-time annihilations of the heavier scalar, in the context of the super-WIMP mechanism.

43 pages, 14 figures, journal version

References in corpus (21)

• The Dawn of FIMP Dark Matter: A Review of Models and Constraints
• Static quark-antiquark pairs at finite temperature
• Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles
• Dark matter production in the early Universe: beyond the thermal WIMP paradigm
• Search for direct production of charginos, neutralinos and sleptons in final states with two leptons and missing transverse momentum in pp collisions at sqrt(s) = 8 TeV with the ATLAS detector
• Searches for electroweak production of charginos, neutralinos, and sleptons decaying to leptons and W, Z, and Higgs bosons in pp collisions at 8 TeV
• Real and imaginary-time $Q\bar{Q}$ correlators in a thermal medium
• Making dark matter out of light: freeze-in from plasma effects
• Thermal production of relativistic Majorana neutrinos: Strong enhancement by multiple soft scattering
• Search for heavy charged long-lived particles in the ATLAS detector in 36.1 fb${}^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV
• On the hadronic contribution to sterile neutrino production
• Signatures of Majorana dark matter with t-channel mediators
• The Extent of the Stop Coannihilation Strip
• Probing the scotogenic FIMP at the LHC
• Effects of QCD bound states on dark matter relic abundance
• Right-handed neutrino production rate at T > 160 GeV
• Low Mass Thermal Dilepton Production at NLO in a Weakly Coupled Quark-Gluon Plasma
• On thermal corrections to near-threshold annihilation
• Re-derived overclosure bound for the inert doublet model
• Interpolation of hard and soft dilepton rates
• Two-loop thermal spectral functions with general kinematics

Cited by in corpus (20)

• Lyman-$\alpha$ constraints on freeze-in and superWIMPs
• Freezing-in a hot bath: resonances, medium effects and phase transitions
• Confronting Dark Matter Freeze-In during Reheating with Constraints from Inflation
• Strong electroweak phase transition in $t$-channel simplified dark matter models
• Dark matter freeze-in from semi-production
• FIMP Dark Matter from Leptogenesis in Fast Expanding Universe
• Freeze-in Dark Matter Through Forbidden Channel in $U(1{)}_{B-L}$
• Bound-state formation, dissociation and decays of darkonium with potential non-relativistic Yukawa theory for scalar and pseudoscalar mediators
• Smooth interpolation between thermal Born and LPM rates
• $t$-channel singularities in cosmology and particle physics
• Thermally corrected masses and freeze-in dark matter: a case study
• Resonant $s$-channel dark matter annihilation at NLO
• Efficient numerical integration of thermal interaction rates
• Impact of bound states on non-thermal dark matter production
• t-channel dark matter at the LHC -- a whitepaper
• Freezing In with Lepton Flavored Fermions
• Feebly-interacting dark matter
• Scattering versus Forbidden Decay in Dark Matter Freeze-in
• Searching for dark radiation at the LHC
• Revisiting freeze-in dark matter from renormalizable operators