A core prediction of natural Supersymmetry is the existence of four light higgsinos not too far above the mass of the Z boson. The small mass splittings amongst the higgsinos -- typically 5-20\,GeV -- imply very little visible energy release from decays of heavier higgsinos. In particular, if other SUSY particles are quite heavy, as can be the case in SUSY with radiatively-driven naturalness, the higgsinos are extremely hard to detect at hadron colliders. The clean environment of electron-positron colliders with s>2mhiggsino, however, would allow for a decisive search for the required light higgsinos. Thus, e+e− colliders should either discover or exclude natural SUSY. We present a detailed study of higgsino pair production at the proposed International Linear e+e− Collider which is under consideration for construction in Japan. A variety of precision measurements should allow for extraction of underlying parameters and provide a window onto physics at the grand unified scale.
@article{arxiv.1611.02846,
title = {Naturalness and light higgsinos: A powerful reason to build the ILC},
author = {Howard Baer and Mikael Berggren and Keisuke Fujii and Suvi-Leena Lehtinen and Jenny List and Tomohiko Tanabe and Jacqueline Yan},
journal= {arXiv preprint arXiv:1611.02846},
year = {2016}
}