The "approach unifying spin and charges" predicts the fourth family and a stable family forming the dark matter clusters

TL;DR

This paper proposes a theoretical framework unifying spin and charges in higher dimensions, predicting four massless and four massive fermion families, with the stable fifth family potentially constituting dark matter and the fourth observable at colliders.

Contribution

It introduces a new approach in higher-dimensional theories that naturally predicts an extra family and a stable family, offering insights into dark matter and collider phenomenology.

Findings

Predicts four massless fermion families consistent with the Standard Model

Identifies a stable fifth family that could form dark matter

Suggests the fourth family may be detectable at the LHC

Abstract

The Approach unifying spin and charges, assuming that all the internal degrees of freedom---the spin, all the charges and the families---originate in $d > (1+3)$ in only two kinds of spins (the Dirac one and the only one existing beside the Dirac one and anticommuting with the Dirac one), is offering a new way in understanding the appearance of the families and the charges (in the case of charges the similarity with the Kaluza-Klein-like theories must be emphasized). A simple starting action in $d >(1+3)$ for gauge fields (the vielbeins and the two kinds of the spin connections) and a spinor (which carries only two kinds of spins and interacts with the corresponding gauge fields) manifests after particular breaks of the starting symmetry the massless four (rather than three) families with the properties as assumed by the Standard model for the three known families, and the additional four massive families. The lowest of these additional four families is stable. A part of the starting action contributes, together with the vielbeins, in the break of the electroweak symmetry manifesting in $d=(1+3)$ the Yukawa couplings (determining the mixing matrices and the masses of the lower four families of fermions and influencing the properties of the higher four families) and the scalar field, which determines the masses of the gauge fields. The fourth family might be seen at the LHC, while the stable fifth family might be what is observed as the dark matter.