The supersymmetric flavour problem in 5D GUTs and its consequences for LHC phenomenology

TL;DR

This paper explores 5D GUT models with localized Higgs and SUSY breaking sectors, showing how hierarchical Yukawa couplings can solve the flavor problem and predicting heavy superpartners with potential LHC signatures.

Contribution

It introduces a detailed analysis of supersymmetric 5D GUT models with wave function profiles, addressing flavor hierarchies and experimental constraints, including lepton flavor violation.

Findings

Hierarchical fermion masses explained by wave function profiles.

Heavy gluinos and squarks beyond current experimental bounds.

Lepton flavor violation signatures in SUSY cascade decays.

Abstract

We study supersymmetric models with a GUT-sized extra dimension, where both the Higgs fields and the SUSY breaking hidden sector are localized on a 4D brane. Exponential wave function profiles of the matter fields give rise to hierarchical structures in the Yukawa couplings and soft terms. Such structures can naturally explain hierarchical fermion masses and mixings, while at the same time alleviating the supersymmetric flavour problem. We discuss two sources of supersymmetry breaking, radion mediation and brane fields, and perform a detailed numerical analysis, thoroughly taking into account the proliferation of unknown O(1) coefficients that occurs in this class of models. It turns out that additional assumptions on supersymmetry breaking are necessary to evade the stringent experimental bounds on lepton flavour violation. The favourable regions of parameter space are then examined with regards to their LHC phenomenology. They generically feature heavy gluinos and squarks beyond current bounds. Lepton flavour violation in SUSY cascade decays can give interesting signatures.