Impact of Evaporation Barriers on Solar-Captured Dark Matter Distribution and Evaporation Mass

Abstract

Evaporation determines the low-mass reach of solar-captured dark matter because that reach is controlled by the small population of particles closest to the escape threshold. We present an orbit-space calculation of the non-thermal distribution of captured dark matter in the presence of an evaporation barrier generated by a smooth in-medium attraction sourced by the solar medium. We show that the barrier not only deepens the effective potential but also reshapes the near-threshold phase-space structure, displacing the equilibrium distribution away from weakly bound, escape-prone trajectories and toward more tightly bound core-crossing orbits, thereby suppressing evaporation and lowering the evaporation mass. Although the bulk population remains near thermal equilibrium, the near-threshold tail, as reflected in the projected velocity spectrum, acquires characteristic non-thermal structure because the barrier deforms the bound orbit space and preferentially retains particles that repeatedly traverse the hot solar core. The near-threshold tail is therefore essential for determining the low-mass reach of solar dark-matter searches in the barrier regime, and our orbit-space treatment captures the relevant physics in a controlled way.

arXiv comment12 pages, 5 figures

References in corpus (28)

• Supersymmetric Dark Matter
• Letter of Intent for KM3NeT 2.0
• Precise Relic WIMP Abundance and its Impact on Searches for Dark Matter Annihilation
• First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment
• The Effective Field Theory of Dark Matter Direct Detection
• IceCube-Gen2: The Window to the Extreme Universe
• First Direct Detection Limits on sub-GeV Dark Matter from XENON10
• First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment
• Light Dark Matter: Models and Constraints
• New Solar Composition: The Problem With Solar Models Revisited
• Model-independent WIMP Scattering Responses and Event Rates: A Mathematica Package for Experimental Analysis
• Non-relativistic effective theory of dark matter direct detection
• A review of indirect searches for particle dark matter
• SENSEI: First Direct-Detection Constraints on sub-GeV Dark Matter from a Surface Run
• Direct dark matter detection: the next decade
• Limits on Dark Matter Annihilation in the Sun using the ANTARES Neutrino Telescope
• Dark Matter Search Results from 1.54 Tonne$\cdot$Year Exposure of PandaX-4T
• Dark matter in the Sun: scattering off electrons vs nucleons
• On the Minimum Dark Matter Mass Testable by Neutrinos from the Sun
• Evaporation of dark matter from celestial bodies
• Search for GeV-scale Dark Matter Annihilation in the Sun with IceCube DeepCore
• Evaporation and scattering of momentum- and velocity-dependent dark matter in the Sun
• Dark Matter Indirect Signatures
• Probing Light Dark Matter via Evaporation from the Sun
• Constraints on heavy decaying dark matter from 570 days of LHAASO observations
• Evaporation Barrier for Dark Matter in Celestial Bodies
• Thermalization time scales for WIMP capture by the Sun in effective theories
• On the evaporation of solar dark matter: spin-independent effective operators