Soft Masses in Theories with Supersymmetry Breaking by TeV-Compactification
I. Antoniadis, S. Dimopoulos, A. Pomarol, M. Quiros
TL;DR
This paper investigates supersymmetry breaking via Scherk-Schwarz compactification in theories with TeV-scale extra dimensions, highlighting the resulting UV-insensitive soft terms and the distinctive sparticle spectrum. Scalar sparticles acquire one-loop masses that are only logarithmically sensitive to the UV cutoff, while gauginos and Higgsinos sit at the higher compactification scale, producing a highly hierarchical pattern. Electroweak symmetry breaking is driven by stop-induced radiative corrections, with a dynamical mechanism able to set the compactification radius M_c at the TeV scale through a radiative minimum of the vacuum energy. The framework is highly predictive, controlled by a small set of parameters, and implies heavy KK modes inaccessible at the LHC, but offers distinctive collider and cosmological implications for the LSP and radius stabilization. The work also discusses how a hierarchical compactification radius can be dynamically determined and the role of bulk cosmological-constant cancellations in making the scenario viable.
Abstract
We study the sparticle spectroscopy and electroweak breaking of theories where supersymmetry is broken by compactification (Scherk-Schwarz mechanism) at a TeV. The evolution of the soft terms above the compactification scale and the resulting sparticle spectrum are very different from those of the usual MSSM and gauge mediated theories. This is traced to the softness of the Scherk-Schwarz mechanism which leads to scalar sparticle masses that are only logarithmically sensitive to the cutoff starting at two loops. As a result, squarks and sleptons are naturally an order of magnitude lighter than gauginos. In addition, the mechanism is very predictive and the sparticle spectrum depends on just two new parameters. A significant advantage of this mechanism relative to gauge mediation is that a Higgsino mass $μ\sim M_susy$ is automatically generated when supersymmetry is broken. Our analysis applies equally well to theories where the cutoff is near a TeV or $M_{Pl}$ or some intermediate scale. We also use these observations to show how we may obtain compactification radii which are hierarchically larger than the fundamental cutoff scale.