Isospin-violating dark matter in a U(1)′ model inspired by E6

摘要

We propose a U ( 1 ) ′ model inspired by E 6 , which has an isospin-violation dark matter. With extra an two pairs of vectorlike quarks, we can assign the proper U ( 1 ) ′ charges for the first two-generation quark doublets and explain why the first two-generation quarks are lighter than the third generation. By choosing a proper linear combination of two extra U ( 1 ) gauge symmetries in E 6 , it is natural to realize the ratio f n / f p = ? 0.7 so as to maximally relax the constraints from the xenon based direct detection experiments. We study the sensitivities of the dark matter direct and indirect detection experiments and identify the parameter spaces that can give the observed relic density. We also study the sensitivities of the future colliders with a center mass energy s = 33 / 50 / 100 ? ? TeV and compare the different detection methods. We show that in some parameter spaces, the future colliders can give much stronger limits.