KEK Theory Seminar(Dr.Yu Hamada)
Two Higgs doublet model (2HDM), in which one more Higgs doublet is added to the Standard Model(SM), is one of the most simple extensions of the SM. 2HDM allows a solitonic object called as the Nambu monopole, which is a magnetic monopole attached with two vortex strings. We show that the monopole is topologically stable when the Higgs potential has a global U(1) symmetry and a Z2Z2 symmetry. We also discuss phenomenological implications of the monopole. This talk is based on arXiv:1904.09269 and 2003.08772.