A New Direction in Dark-Matter Complementarity: Dark-Matter Decay as a Complementary Probe of Multi-Component Dark Sectors

TL;DR

This paper explores how dark-matter decay from heavier to lighter components offers a new complementary approach to existing dark-matter detection methods, especially in multi-component models.

Contribution

It introduces a novel 'diagonal' complementarity in multi-component dark matter theories through decay processes, expanding the scope of dark-matter search strategies.

Findings

Decay processes provide additional constraints on multi-component dark matter models.

Enhanced complementarity improves the ability to probe dark-matter parameter space.

Decay channels can correlate with other detection techniques, strengthening overall constraints.

Abstract

In single-component theories of dark matter, the $2\to 2$ amplitudes for dark-matter production, annihilation, and scattering can be related to each other through various crossing symmetries. These crossing relations lie at the heart of the celebrated complementarity which underpins different existing dark-matter search techniques and strategies. In multi-component theories of dark matter, by contrast, there can be many different dark-matter components with differing masses. This then opens up a new, "diagonal" direction for dark-matter complementarity: the possibility of dark-matter decay from heavier to lighter dark-matter components. In this work, we discuss how this new direction may be correlated with the others, and demonstrate that the enhanced complementarity which emerges can be an important ingredient in probing and constraining the parameter spaces of such models.