Abelian Extension of Standard Model with Four Generations

Abstract

An abelian gauge extension of the Standard Model is proposed with a fourth generation. The fourth generation fermions obtain their masses from a heavier Higgs doublet which makes no tree level contributions to the first three generations masses. Light first three generations neutrino masses continue to have type I seesaw explanation whereas the fourth generation neutrino turns out to be a heavy Dirac neutrino. In the minimal version of such a model with no off-diagonal Yukawa couplings between the fourth and the first three generation, such a heavy Dirac neutrino can be long lived on cosmological time scales. In this model the stated LHC exclusion range $120\text{GeV}<m_H<600\text{GeV}$ on the lighter Higgs placed in the context of generic fourth generation standard model is evaded. Also, the Dirac fourth generation neutrino in this model, if stable would constitute upto 1% of the cold Dark Matter in the Universe.

12 pages, 1 figure, Journal Version

References in corpus (2)

• The discovery of the fourth family at the LHC: what if?
• A fourth generation, anomalous like-sign dimuon charge asymmetry and the LHC

Cited by in corpus (8)

• Deviations from Tri-Bimaximal Neutrino Mixing Using Type II Seesaw
• Fourth Generation Parity
• Large mass splittings for fourth generation fermions allowed by LHC Higgs exclusion
• Abelian Gauge Extension of Standard Model: Dark Matter and Radiative Neutrino Mass
• Common Radiative Origin of Active and Sterile Neutrino Masses
• Quasi-Degenerate Neutrinos in Type II Seesaw Models
• Mass-varying Dark Matter from a Phase Transition
• Gauged $L_e-L_{\mu }-L_{\tau }$ symmetry, fourth generation, neutrino mass and dark matter