Finite theories before and after the discovery of a Higgs boson at the LHC

Abstract

Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) which can be made finite to all‐loop orders, based on the principle of reduction of couplings, and therefore are provided with a large predictive power. Confronting the predictions of SU(5) FUTs with the top and bottom quark masses and other low‐energy experimental constraints a light Higgs‐boson mass in the range Mh ∼ 121–126 GeV was predicted, in striking agreement with the recent discovery of a Higgs‐like state around ∼ 125.5 GeV at ATLAS and CMS. Furthermore the favoured model, a finiteness constrained version of the MSSM, naturally predicts a relatively heavy spectrum with coloured supersymmetric particles above ∼ 1.5 TeV, consistent with the non‐observation of those particles at the LHC. Restricting further the best FUT's parameter space according to the discovery of a Higgs‐like state and B‐physics observables we find predictions for the rest of the Higgs masses and the supersymmetric particle spectrum.

Reduction of Couplings in Quantum Field Theories with Applications in Finite Theories and the MSSM

“…Without any M h restrictions the coloured SUSY particles have masses above ∼ 1.8 TeV in agreement with the nonobservation of those particles at the LHC [68][69][70]. Including the Higgs mass constraints in general favours the lower part of the SUSY particle mass spectra, but also cuts away the very low values [97][98][99][100]. Going to the anticipated future theory uncertainty of M h (as shown in the right plot of Fig.…”

Reduction of couplings and its application in particle physics

“…In our analysis of FUT [195] we included restrictions of third generation quark masses and B-physics observables and it proved consistent with all the phenomenological constraints. Compared to our previous analyses [119,120,196,[207][208][209], the improved evaluation of M h prefers a heavier (Higgs) spectrum and thus allows only a heavy supersymmetric spectrum. The coloured spectrum easily escapes (HL-)LHC searches, but can likely be tested at the FCChh.…”

The LHC Higgs Boson Discovery: Updated Implications for Finite Unified Theories and the SUSY Breaking Scale

“…The model, SU(5)-FUT (with µ < 0), is consistent with all the phenomenological constraints. Compared to our previous analyses [46,47,136,137], the improved evaluation of M h prefers a heavier (Higgs) spectrum and thus in general allows only a very heavy SUSY spectrum. The colored spectrum could easily escapes the (HL-)LHC searches, but can likely be tested at the FCC-hh.…”