Leptogenesis as an origin of dark matter and baryon asymmetries in the E6 inspired SUSY models

TL;DR

This paper investigates how leptogenesis in E6 inspired SUSY models can generate both dark matter and baryon asymmetries, highlighting the role of exotic matter and right-handed neutrino decays.

Contribution

It introduces a novel leptogenesis mechanism within E6 inspired SUSY models involving exotic matter and specific decay processes of right-handed neutrinos.

Findings

Lightest exotic fermions are stable and form hot dark matter.

Right-handed neutrino decays can produce the observed baryon asymmetry.

Leptogenesis is viable with neutrino masses around 10^6-10^7 GeV.

Abstract

We explore leptogenesis within the E6 inspired U(1) extension of the MSSM in which exact custodial symmetry forbids tree-level flavour-changing transitions and the most dangerous baryon and lepton number violating operators. This supersymmetric (SUSY) model involves extra exotic matter beyond the MSSM. In the simplest phenomenologically viable scenarios the lightest exotic fermions are neutral and stable. These states should be substantially lighter than 1 eV forming hot dark matter in the Universe. The low-energy effective Lagrangian of the SUSY model under consideration possesses an approximate global U(1)_E symmetry associated with the exotic states. The U(1)_E symmetry is explicitly broken because of the interactions between the right-handed neutrino superfields and exotic matter supermultiplets. As a consequence the decays of the lightest right-handed neutrino/sneutrino give rise to both U(1)_E and U(1)_{B-L} asymmetries. When all right-handed neutrino/sneutrino are relatively light \sim 10^6-10^7 GeV the appropriate amount of the baryon asymmetry can be induced via these decays if the Yukawa couplings of the lightest right-handed neutrino superfields to the exotic matter supermultiplets vary between 10^{-4}-10^{-3}.