Implications of an axino LSP for naturalness

Understand

Both the naturalness of the electroweak symmetry breaking and the resolution of the strong CP problem may require a small Higgsino mass $\mu$ generated by a realization of the DFSZ axion model.

• Assuming the axino is the lightest supersymmetric particle, we study its implications on $\mu$ and the axion scale.
• Copiously produced light Higgsinos at collider (effectively only neutral NLSP pairs) eventually decay to axinos leaving prompt multi-leptons or displaced vertices which are being looked for at the LHC.
• We use latest LHC7+8 results to derive current limits on $\mu$ and the axion scale.