Probing Unified Theories with Reduced Couplings at Future Hadron Colliders

TL;DR

This paper reviews theories with reduced couplings in supersymmetric GUTs, explores their collider signatures, and assesses their testability at current and future hadron colliders, highlighting the challenges in detecting heavy supersymmetric spectra.

Contribution

It introduces benchmark scenarios for reduced coupling models and evaluates their observability at future colliders, extending the understanding of supersymmetric GUTs.

Findings

Heavy spectra are beyond 14 TeV HL-LHC reach.

Reduced MSSM is ruled out by current LHC data.

FCC-hh can test large parts of the models' spectra.

Abstract

The search for renormalization group invariant relations among parameters to all orders in perturbation theory constitutes the basis of the reduction of couplings concept. Reduction of couplings can be achieved in certain $N=1$ supersymmetric Grand Unified Theories and few of them can become even finite at all loops. We review the basic idea, the tools that have been developed as well as the resulting theories in which successful reduction of couplings has been achieved so far. These include: (i) a reduced version of the minimal $N = 1$ $SU(5)$ model, (ii) an all-loop finite $N = 1$ $SU(5)$ model, (iii) a two-loop finite $N = 1$ $SU(3)^3$ model and finally (vi) a reduced version of the Minimal Supersymmetric Standard Model. In this paper we present a number of benchmark scenarios for each model and investigate their observability at existing and future hadron colliders. The heavy supersymmetric spectra featured by each of the above models are found to be beyond the reach of the 14 TeV HL-LHC. It is also found that the reduced version of the MSSM is already ruled out by the LHC searches for heavy neutral MSSM Higgs bosons. In turn the discovery potential of the 100 TeV FCC-hh is investigated and found that large parts of the predicted spectrum of these models can be tested, but the higher mass regions are beyond the reach even of the FCC-hh.