Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
Department of Physics, Stanford University, Stanford, California 94305, USA.
Phys Rev Lett. 2015 Sep 18;115(12):121801. doi: 10.1103/PhysRevLett.115.121801. Epub 2015 Sep 16.
We study asymmetric dark matter (ADM) in the context of the minimal (fraternal) twin Higgs solution to the little hierarchy problem, with a twin sector with gauged SU(3)^{'}×SU(2)^{'}, a twin Higgs doublet, and only third-generation twin fermions. Naturalness requires the QCD^{'} scale Λ_{QCD}^{'}≃0.5-20 GeV, and that t^{'} is heavy. We focus on the light b^{'} quark regime, m_{b^{'}}≲Λ_{QCD}^{'}, where QCD^{'} is characterized by a single scale Λ_{QCD}^{'} with no light pions. A twin baryon number asymmetry leads to a successful dark matter (DM) candidate: the spin-3/2 twin baryon, Δ^{'}∼b^{'}b^{'}b^{'}, with a dynamically determined mass (∼5Λ_{QCD}^{'}) in the preferred range for the DM-to-baryon ratio Ω_{DM}/Ω_{baryon}≃5. Gauging the U(1)^{'} group leads to twin atoms (Δ^{'}-τ^{'}[over ¯] bound states) that are successful ADM candidates in significant regions of parameter space, sometimes with observable changes to DM halo properties. Direct detection signatures satisfy current bounds, at times modified by dark form factors.
我们研究了非对称暗物质（ADM）在最小（兄弟）双胞胎希格斯解决方案的背景下，这个方案解决了小等级问题，有一个带有规范的 SU(3)^{'}×SU(2)^{'}的双胞胎部分，一个双胞胎希格斯二重态，以及只有第三代双胞胎费米子。自然性要求 QCD^{'} 标度 Λ_{QCD}^{'}≃0.5-20 GeV，并且 t^{'} 是重的。我们专注于轻 b^{'} 夸克区域，m_{b^{'}}≲Λ_{QCD}^{'}，其中 QCD^{'} 的特征是单个标度 Λ_{QCD}^{'}，没有轻的π介子。双胞胎重子数不对称导致了一个成功的暗物质（DM）候选者：自旋为 3/2 的双胞胎重子，Δ^{'}∼b^{'}b^{'}b^{'}，其质量（∼5Λ_{QCD}^{'})是在 DM 与重子比例 Ω_{DM}/Ω_{baryon}≃5 的首选范围内。规范 U(1)^{'} 群导致双胞胎原子（Δ^{'}-τ^{'}[over ¯]束缚态），在参数空间的重要区域中是成功的 ADM 候选者，有时会对 DM 晕的性质产生可观测的变化。直接探测特征满足当前的限制，有时会被暗形式因子修改。
