String scale unification in an SU(6) × SU(2) GUT

Abstract

We construct and analyze an SU(6)×SU(2) GUT. The model is k=1 string embedable in the sense that we employ only chiral representations allowed at the k=1 level of the associated Kač-Moody Algebra. Both cases SU(6) × SU(2) L and SU(6) × SU(2) R are realized. The model is characterized by the SU(6) × SU(2) → SU(4) × SU(2) × SU(2) breaking scale M X , and theThe spectrum bellow M R includes an extra pair of charge-1/3 colour-triplets of mass M I ≤ M R that does not couple to matter fields and, possibly, an extra pair of isodoublets. Above M X the SU(6) and SU(2) gauge couplings always unify at a scale which can be taken to be the string unification scale M s ∼ 5 × 1017 GeV . The model has Yukawa coupling unification since quarks and leptons obtain their masses from a single Yukawa coupling. Neutrinos obtain acceptably small masses through a see-saw mechanism. Coloured triplets that couple to matter fields are naturally split from the coexisting isodoublets without the need of any numerical fine tuning.

Supersymmetry breaking scalar masses and trilinear soft terms from high-dimensional operators in SUSY GUT

“…This symmetry breaking chain was proposed in [64]. The decomposition of 27 representation of E 6 in terms of gauge group…”

Proton stability inSU(5)×U(1)andSU(6Faraggi1, Rizos2, Tamvakis3 2014Phys. Rev. DSelf Cite2020View full textAdd to dashboardCite

“…One possibility is the SU (6)×SU (2) gauge group, a maximal subgroup of E 6 , which also allows us to implement the "deunification" scenario for proton decay suppression. There are two possible embeddings of the weak isospin in this gauge group, namely SU (6) × SU (2) L and SU (6) × SU (2) R [10]. However, only the SU (6) × SU (2) R gauge symmetry admits an SU (5) × U (1) X subgroup.…”

“…where N c H , N c H are the singlets residing in H (10,1) , H (10,−1) of the SU (5) × U (1) subgroup respectively and…”

“…along the SM singlet direction of the Higgs fields H(10,1) , H(10,−1) . The remnants of the Higgs mechanism comprise a pair of triplets D c H , D c H and one singlet (N c H…”

Infinite Classes of Cases with Non-trivial Anomaly Cancellation

“…Consider for example, the fermion multiplets of one family in Flipped SU (5). Under the SU( 5) ×U(1) they transform as 10 1 + 5 −3 + 1 5 , where the superscripts denote the U(1) charges.…”