Estimation of the Density of the Self-Interacting Dark-Matter Component within a Clump with Allowance for Recombination

The model of dark matter featuring a component in the form of free particles and antiparticles (a, #Latin Small Letter A With Macron# ) possessing self-interaction of the Coulomb type is considered. Darkmattermay form small-scale clumps where the annihilation of particles a and #Latin Small Letter A With Macron# is enhanced. This annihilation may lead to observable effects (in cosmic rays, for example) and/or to the destruction of these clumps. However, there is an ambiguity in describing the annihilation (via recombination) of very slow particles, which may include a and #Latin Small Letter A With Macron# in clumps. The effect of annihilation (in terms of the residual number of free particles a and #Latin Small Letter A With Macron# in clumps) is estimated within two approaches (simplified quantum-mechanical and classical) at chosen parameter values.