Weakly-interacting massive particles in non-supersymmetric SO(10) grand unified models

Abstract

Abstract: Non-supersymmetric SO(10) grand unified theories provide a framework in which the stability of dark matter is explained while gauge coupling unification is realized. In this work, we systematically study this possibility by classifying weakly interacting dark matter candidates in terms of their quantum numbers of SU(2)L ⊗ U(1)Y , B − L, and SU(2)R. We consider both scalar and fermion candidates. We show that the requirement of a sufficiently high unification scale to ensure a proton lifetime compatible with experimental constraints plays a strong role in selecting viable candidates. Among the scalar candidates originating from either a 16 or 144 of SO(10), only SU(2)L singlets with zero hypercharge or doublets with Y = 1/2 satisfy all constraints for SU(4)C ⊗ SU(2)L ⊗ SU(2)R and SU(3)C ⊗ SU(2)L ⊗ SU(2)R ⊗ U(1)B−L intermediate scale gauge groups. Among fermion triplets with zero hypercharge, only a triplet in the 45 with intermediate group SU(4)C ⊗ SU(2)L ⊗ SU(2)R leads to solutions with MGUT> Mint and a long proton lifetime. We find three models with weak doublets and Y = 1/2 as dark matter candidates for the SU(4)C ⊗ SU(2)L ⊗ SU(2)R and SU(4)C ⊗ SU(2)L ⊗ U(1)R intermediate scale gauge groups assuming a minimal Higgs content. We also discuss how these models may be tested at accelerators and in dark matter detection experiments.