Low Scale Supersymmetry Breaking and its LHC Signatures

TL;DR

This paper explores low-scale supersymmetry breaking within the MSSM framework, analyzing how goldstino interactions modify Higgs couplings and how LHC data constrains the supersymmetry breaking scale.

Contribution

It introduces a comprehensive effective Lagrangian for low-scale SUSY breaking, including goldstino dynamics and higher-dimensional operators, extending previous models.

Findings

Goldstino interactions significantly alter Higgs couplings.

LHC bounds place constraints on the supersymmetry breaking scale f.

Higher-dimensional operators modify the relation between goldstino couplings and soft terms.

Abstract

We study the most general extension of the MSSM Lagrangian that includes scenarios in which supersymmetry is spontaneously broken at a low scale f. The spurion that parametrizes supersymmetry breaking in the MSSM is promoted to a dynamical superfield involving the goldstino, with (and without) its scalar superpartner, the sgoldstino. The low energy effective Lagrangian is written as an expansion in terms of m_{SUSY}/sqrt{f}, where m_{SUSY} is the induced supersymmetry breaking scale, and contains, in addition to the usual MSSM Lagrangian with the soft terms, couplings involving the component fields of the goldstino superfield and the MSSM fields. This Lagrangian can provide significant corrections to the usual couplings in the Standard Model and the MSSM. We study how these new corrections affect the Higgs couplings to gauge bosons and fermions, and how LHC bounds can be used in order to constrain f. We also discuss that, from the effective field theory point of view, the couplings of the goldstino interactions are not determined by any symmetry, and their usual simple relation to the soft terms is corrected by higher-dimensional operators.