科研之友
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摘要
We discuss dark matter (DM) physics in the Type-I inert two-Higgs-doublet model (2HDM) with local U(1) H Higgs gauge symmetry, which is assigned to the extra Higgs doublet in order to avoid the Higgs-mediated flavor problems. In this gauged inert DM setup, a U(1)(H)-charged scalar Phi is also introduced to break U(1)(H) spontaneously through its nonzero vacuum expectation value (VEV), , and then the remnant discrete subgroup appears according to the U(1)(H) charge assignment of Phi. The U(1)(H)-charged Higgs doublet does not have Yukawa couplings with the Standard-Model (SM) fermions, and its lightest neutral scalar component H is stable because of the remnant discrete symmetry. In order to suppress a too large Z-exchange diagram contribution in DM direct detection experiments, we have to introduce a non-renormalizable operator which can be generated by integrating out an extra heavy scalar. With these new particles contents, we first investigate the constraint on the U(1)(H) gauge interaction, especially through the kinetic and mass mixing between the SM gauge bosons and the extra gauge boson. Then we discuss dark matter physics in our 2HDM: thermal relic density, and direct/indirect detections of dark matter. The additional U(1) (H) gauge interaction plays a crucial role in reducing the DM thermal relic density. The most important result within the inert DM model with local U(1)(H) symmetry is that similar to O(10) GeV dark matter scenario, which is strongly disfavored in the usual Inert Doublet Model (IDM) with Z(2) symmetry, is revived in our model because of newly open channels, HH -> Z(H)Z(H), Z(H)Z. Exotic Higgs decays, h -> Z(H)Z(H), ZZ(H), would be distinctive signatures of the inert 2HDM with local U(1)(H) symmetry.
- 出版日期2014-11-12
