The naturalness principle and expectations for a linear collider

Abstract

Naturalness considerations are frequently used to place theoretical upper limits on the masses of new particles in supersymmetric extensions of the standard model. These theoretical limits, in turn, shape our expectations of how likely it is that new physics will be discovered at any particular collider. A significant portion of the literature devoted to naturalness studies apply criteria which do not have a reliable correspondence to fine-tuning. This report discusses the principled method for quantifying naturalness, and presents theoretical bounds on sparticle masses in two scenarios.