Axinos in Cosmology and at Colliders

Understand

The axino, the fermionic superpartner of the axion, is a well-motivated candidate for cold dark matter if it is the lightest supersymmetric particle.

• Since the axino couples very weakly to the matter multiplets, the next-to-lightest supersymmetric particle (NLSP) has a long lifetime, which has important consequences for both cosmology and collider phenomenology.
• Assuming that a charged slepton is the NLSP, we calculate the complete leading one- and two-loop contributions to its decay.
• We analyze in detail constraints on the parameters space from cosmology and discuss how this scenario can be probed at colliders.