Howard Baer (University of Oklahoma)Dr Jenny List (DESY)
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-- implies 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 $E>2m(higgsino)$, 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.
Howard Baer (University of Oklahoma) Dr Jenny List (DESY)
Ms Jackie Yan (Tokyo) Dr Keisuke Fujii (KEK) Dr Mikael Berggren (DESY) Ms Suvi Lehtinen (DESY) Dr Tomohiko Tanabe (Tokyo)