论文标题
狄拉克暗物质，深色辐射和替代$ u（1）_x $标准模型中的II类Seesaw机制
Dirac dark matter, dark radiation, and the type-II seesaw mechanism in alternative $U(1)_X$ standard model
论文作者
论文摘要
我们为右撇子中微子提供了一个额外的$ u（1）_x $模型。三胞胎Higgs领域的II型Seesaw机制由于替代电荷分配而有望产生中微子质量。一个额外的希格斯双峰的较小的真空期望值（VEV）自然会导致三胞胎希格斯场的一小部分，因此，可以理解中微子质量的较小性。借助$ U（1）_x $的最小Higgs Field带有收费$ 1 $，右撇子中微子是Dirac Dark Matter（DM）和Dark Radiation（DR）的候选人。我们在广泛的参数空间范围内得出并强加了LHC结合，DR约束和DM直接搜索的界限。在各种$ u（1）_x $选择中，DM直接搜索结合的限制是$ u（1）_r $最弱的，其中thermal DM和不可忽略的DR的约束可以兼容。从所谓的哈勃张力的角度来看，这种有效的中微子物种将很有趣。
We propose an extra $U(1)_X$ model with an alternative charge assignment for right-handed right-handed neutrinos. The type-II seesaw mechanism by a triplet Higgs field is promising for neutrino mass generation because of the alternative charge assignment. The small vacuum expectation value (VEV) of an additional Higgs doublet naturally leads to a very small VEV of the triplet Higgs field, and as a result, the smallness of neutrino mass can be understood. With the minimal Higgs field for $U(1)_X$ with the charge $1$, right-handed neutrinos are candidates for Dirac dark matter (DM) and dark radiation (DR). We have derived and imposed the LHC bound, the DR constraint and the bound from DM direct searches in the wide range of parameter space. Among various $U(1)_X$ choices, the DM direct search bound is found to be weakest for $U(1)_R$ where the constraints from thermal DM and non-negligible DR can be compatible. Such a number of the effective neutrino species would be interesting from the viewpoint of the so-called Hubble tension.
