Theories with Gauge-Mediated Supersymmetry Breaking

TL;DR

The work surveys gauge-mediated supersymmetry breaking (GMSB) as a compelling alternative to gravity mediation, highlighting its natural suppression of flavour violation and its predictive sparticle mass spectrum. It details the architecture consisting of a visible sector, a SUSY-breaking secluded sector, and a messenger sector that transmits breaking via gauge interactions, yielding one-loop gaugino masses and two-loop scalar masses. The review covers the full theoretical framework, nonperturbative tools for dynamical SUSY breaking, and a wide range of explicit models, including those with dynamical or composite messengers, while addressing the mu/Bmu problem and phenomenological implications. It discusses collider and low-energy signatures, gravitino cosmology, and dark matter prospects, emphasizing the distinctive, testable predictions of GMSB in contrast to gravity-mediated scenarios. The paper also notes ongoing developments and open questions in building fully realistic, dynamically generated GMSB frameworks.

Abstract

Theories with gauge-mediated supersymmetry breaking provide an interesting alternative to the scenario in which the soft terms of the low-energy fields are induced by gravity. These theories allow for a natural suppression of flavour violations in the supersymmetric sector and have very distinctive phenomenological features. Here we review their basic structure, their experimental implications, and the attempts to embed them into models in which all mass scales are dynamically generated from a single fundamental scale.

Figures (12)

• Figure 1: Feynman diagrams contributing to supersymmetry-breaking gaugino ($\lambda$) and sfermion ($\tilde{f}$) masses. The scalar and fermionic components of the messenger fields $\Phi$ are denoted by dashed and solid lines, respectively; ordinary gauge bosons are denoted by wavy lines.
• Figure 2: The functions $f(x)$, $g(x)$, and $\sqrt{f(x)}$.
• Figure 3: Different supersymmetric particle masses in units of the $B$-ino mass $M_1$, as a function of the messenger mass $M$. The choice of parameters is indicated, and in both cases it corresponds to a $B$-ino mass of 100 GeV.
• Figure 4: Slepton masses as a function of the $B$-ino mass $M_1$, for the indicated choice of parameters. Dashed lines correspond to the case of vanishing $D$ terms ($\tan \beta =1$), and the solid lines to the case of maximal $D$ terms ($\cos 2\beta =-1$).
• Figure 5: The ratio between $\mu$ and the $B$-ino mass $M_1$, as a function of the messenger mass $M$. The choice of parameters is indicated, and in both cases it corresponds to a $B$-ino mass of 100 GeV.