Precision gaugino mass measurements as a probe of large trilinear soft terms at the ILC

In supersymmetric models with radiatively driven naturalness, Higgsino-like electroweak-inos are expected to lie in a mass range 100-300 GeV, the lighter the more natural. Such states can be pair produced at high rates at the International Linear e+e- Collider where their masses are nearly equal to the value of the superpotential μ parameter while their mass splittings depend on the gaugino masses M1 and M2. The gaugino masses in turn depend on trilinear soft terms - the A parameters, which are expected to lie in the multi-TeV range owing to the 125 GeV Higgs mass - via two-loop contributions to renormalization group running. We examine the extent to which the International Linear e+e- Collider is sensitive to large A terms via precision electroweak-ino mass measurement. Extraction of gaugino masses at the percent level or below should allow for interesting probes of large trilinear soft supersymmetry breaking terms under the assumption of unified gaugino masses.