Gravitational waves from a dark $U(1)_D$ phase transition in the light of NANOGrav 12.5 yr data [CL]

http://arxiv.org/abs/2105.01007


We study the possibility of having a strong first order phase transition (FOPT) below the electroweak scale within $U(1)_D$ gauge extension of the standard model. As pointed out recently by the NANOGrav collaboration, gravitational waves from such a phase transition with appropriate strength and nucleation temperature can explain their 12.5 yr data. We first find the parameter space of this minimal model consistent with NANOGrav findings considering only a complex singlet scalar and $U(1)_D$ vector boson. Existence of a singlet fermion charged under $U(1)_D$ can give rise to dark matter in this model while incorporating additional scalars can also explain light neutrino masses radiatively.

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D. Borah, A. Dasgupta and S. Kang
Tue, 4 May 21
27/72

Comments: 5 pages, 2 captioned figures