Low fine-tuning in Yukawa-deflected gauge mediation

Abstract

We discuss a class of models with gauge-mediated supersymmetry breaking characterized by a non-unified messenger sector inducing non-standard gaugino mass ratios, as well as by additional contributions to the soft mass terms from a matter-messenger coupling. The well-known effect of this coupling is to generate A-terms at one-loop level, hence raising the Higgs mass without relying on super-heavy stops. At the same time, a hierarchy between Wino and gluino masses, as induced by the non-unified messenger fields, can greatly lower the radiative corrections to the Higgs soft mass term driven by the high-energy parameters, thus reducing the fine tuning. We search for models with low fine tuning within this scenario, and we discuss the spectrum, collider phenomenology, constraints, and prospects of the found solutions. We find that some setups are accessible or already excluded by searches at the Large Hadron Collider, and all our scenarios with a tuning better than about 2\% can be tested at the International Linear Collider.