E6inspired supersymmetric models with exact custodial symmetry

Abstract

The breakdown of E 6 gauge symmetry at high energies may lead to supersymmetric (SUSY) models based on the Standard Model (SM) gauge group together with extra U (1) ψ and U (1) χ gauge symmetries. To ensure anomaly cancellation the particle content of these E 6 inspired models involves extra exotic states that generically give rise to non-diagonal flavour transitions and rapid proton decay. We argue that a single discreteZ H 2 symmetry can be used to forbid tree-level flavor-changing transitions, as well as the most dangerous baryon and lepton number violating operators.We present 5D and 6D orbifold GUT constructions that lead to the E 6 inspired SUSY models of this type. The breakdown of U (1) ψ and U (1) χ gauge symmetries that preserves E 6 matter parity assignment guarantees that ordinary quarks and leptons and their superpartners, as well as the exotic states which originate from 27 representations of E 6 survive to low energies. These E 6 inspired models contain two dark-matter candidates and must also include additional TeV scale vectorlike lepton or vectorlike down type quark states to render the lightest exotic quark unstable. We examine gauge coupling unification in these models and discuss their implications for collider phenomenology and cosmology.

Non-standard higgs decays in U(1) extensions of the MSSM

“…As a consequence the gauge coupling unification remains almost exact in the one-loop approximation. It was also shown that in the two-loop approximation the unification of the gauge couplings in the SUSY models under consideration can be achieved for any phenomenologically acceptable value of the strong coupling α 3 (M Z ) at the scale M Z , consistent with the measured central low-energy value [15,66].…”

“…In this section, we briefly review the E 6 inspired SUSY models with exact custodialZ H 2 symmetry [15], which we then use to demonstrate how light pseudoscalar states can appear in SUSY models with an extra U(1) gauge symmetry. We also consider what kind of Higgs decay rates they can lead to.…”

“…However this term can be eliminated by an appropriate redefinition of the superfield φ, i.e φ → φ − µS/σ. The gauge group and field content of the E 6 inspired SUSY models under consideration can originate from the 5D and 6D orbifold GUT models in which the splitting of GUT multiplets can be naturally achieved [15]. In these orbifold GUT models all GUT relations between the Yukawa couplings can get spoiled while the approximate unification of the SM gauge couplings still takes place.…”

Reviving trinification models through an E6 -extended supersymmetric GUT

“…[5][6][7][8]). One such GUT scenario based upon a maximal rank-6 subgroup ½SUð3Þ 3 ⊂ E 6 and known as gauge trinification (T-GUT) was initially proposed by Glashow in 1984 [9].…”

Exotic Higgs Decays in U(1) Extensions of the MSSM

“…Different aspects of the phenomenology of these E 6 inspired supersymmetric (SUSY) models have been extensively studied in [1,2,3,4,5,6,7,8,9,10,11,12,13].…”