Particle physics and cosmology of the string derived no-scale flipped SU(5)

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2022-04, Vol.82 (4), p.1-23, Article 377
• Main Authors: Antoniadis, I., Nanopoulos, D. V., Rizos, J.
• Format: Article
• Language: English
• Subjects: Analysis; Astronomical models; Astronomy; Astrophysics and Cosmology; Broken symmetry; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Cosmology; Couplings; Eigenvectors; Elementary Particles; Hadrons; Heavy Ions; High Energy Physics - Theory; Inflation (Finance); Large Hadron Collider; Leptons; Mass matrix; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Particle physics; Phenomenology; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quarks; Regular Article - Theoretical Physics; Standard model (particle physics); String Theory; Strings; Supersymmetry
• ISSN: 1434-6052; 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-022-10353-6

In a recent paper, we identified a cosmological sector of a flipped SU (5) model derived in the free fermionic formulation of the heterotic superstring, containing the inflaton and the goldstino superfields with a superpotential leading to Starobinsky type inflation, while S U ( 5 ) × U ( 1 ) is still unbroken. Here, we study the properties and phenomenology of the vacuum after the end of inflation, where the gauge group is broken to the Standard Model. We identify a set of vacuum expectation values, triggered by the breaking of an anomalous U ( 1 ) A gauge symmetry at roughly an order of magnitude below the string scale, that solve the F and D-flatness supersymmetric conditions up to 6th order in the superpotential which is explicitly computed, leading to a successful particle phenomenology. In particular, all extra colour triplets become superheavy guaranteeing observable proton stability, while the Higgs doublet mass matrix has a massless pair eigenstate with realistic hierarchical Yukawa couplings to quarks and leptons. The supersymmetry breaking scale is constrained to be high, consistent with the non observation of supersymmetry signals at the LHC.