Dynamical supersymmetry breaking with a large internal dimension

TL;DR

This work develops a dynamical supersymmetry breaking scenario in string theory with a large internal dimension, yielding a breaking scale $m_s \sim \frac{1}{R}$ and a dynamically generated scale $Q_0$ below the Planck scale via one-loop RG running. Gauginos acquire $M_{1/2}=\frac{1}{2R}$ and twisted matter has no light soft masses, while a natural $μ$ term arises from identifying a Higgs KK mode, with radiative electroweak breaking tying the compactification radius to the top Yukawa coupling $h_t$ and resulting in a low-energy spectrum predicted as a function of the top mass $m_t$. The framework anticipates observable KK excitations, notably a light $\gamma^*$, and yields two viable $m_t$ regions depending on the chosen boundary conditions, thereby tightly constraining the MSSM spectrum. Overall, the approach links SUSY breaking, the electroweak scale, and potential collider signals in a perturbative, dynamical string-theoretic setting.

Abstract

Supersymmetry breaking in string perturbation theory predicts the existence of a new dimension at the TeV scale. The simplest realization of the minimal supersymmetric Standard Model in the context of this mechanism has two important consequences: (i) A natural solution to the $μ$-problem; (ii) The absence of quadratic divergences in the cosmological constant, which leads to a dynamical determination of the supersymmetry breaking and electroweak scale. We present an explicit example in which the whole particle spectrum is given as a function of the top quark mass. A generic prediction of this mechanism is the existence of Kaluza-Klein excitations for gauge bosons and higgses. In particular the first excitation of the photon could be accessible to future accelerators and give a clear signal of the proposed mechanism.