Effective field theory approach to non-relativistic neutralino dark matter pair annihilation processes

The requirement that the thermal relic abundances predicted for the neutralino LSP in the MSSM are consistent with the observed dark matter abundance yields strong constraints to the MSSM parameter space which could help for future identification of a collider candidate as the constituent of cosmic dark matter. For a sufficiently heavy neutralino LSP, threshold effects and mass degeneracies between the LSP and further SUSY particles can play an important role in the determination of the (co-)annihilation cross sections that enter the relic abundance calculation. Using the framework of non-relativistic effective theories, we discuss the (co-)annihilation cross sections of a set of nearly mass degenerate non-relativistic neutralinos and charginos into relativistic Standard Model final states. We thereby provide all perturbative S-wave annihilation rates at next-to-leading order as well as P-wave annihilation rates at leading order in the relative velocity of the annihilating particle pair.