SMART U(1)$$_X$$: standard model with axion, right handed neutrinos, two Higgs doublets and U(1)$$_X$$ gauge symmetry
Eur. Phys. J. C, 80 11 (2020) 1056
Published online: 17 November 2020
DOI: 10.1140/epjc/s10052-020-8343-6