Scalar Dark Matter and Standard Model with Four Generations
Scalar Dark Matter and Standard Model with Four Generations
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DOI：
10.1103/physrevd.82.035016
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发表时间：
2010-04
影响因子：
5
通讯作者：
Xiao-Gang He;Shu-Yu Ho;J. Tandean;Ho-Chin Tsai
中科院分区：
文献类型：
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作者：
Xiao-Gang He;Shu-Yu Ho;J. Tandean;Ho-Chin Tsai
我们考虑一个标量暗物质（DM）模型，$\mathrm{SM}4+\mathrm{D}$，由四代标准模型（SM 4）和一个称为暗子的真实的规范单重标量D$组成，作为WIMP DM候选模型.我们探索的约束下的暗子部门的$\mathrm{SM}4+\mathrm{D}$从WIMP DM直接搜索实验，包括CDMS-II和CoGeNT，并从一个B$介子衰变到一个K介子加上丢失的能量。我们发现，相当大的一部分的暗子参数空间仍然是与实验数据兼容。由于暗子-希格斯相互作用可能会大大增强希格斯的不可见衰变模式，因此暗子的存在可能会导致在第四代夸克存在时对希格斯质量的某些限制减弱或逃避。此外，它可以影响这些新的重夸克衰变为较轻的夸克和希格斯玻色子的变味衰变，因为希格斯玻色子随后可能会以不可见的方式衰变。因此，我们还研究了这些涉及暗子的变味中性跃迁，以及相应的顶夸克衰变，其中一些可能在Tevatron或LHC上观察到，从而为$\mathrm{SM}4+\mathrm{D}$提供了额外的测试。
We consider a scalar dark-matter (DM) model, the $\mathrm{SM}4+\mathrm{D}$, consisting of the standard model with four generations (SM4) and a real gauge-singlet scalar called darkon, $D$, as the WIMP DM candidate. We explore constraints on the darkon sector of the $\mathrm{SM}4+\mathrm{D}$ from WIMP DM direct-search experiments, including CDMS-II and CoGeNT, and from the decay of a $B$ meson into a kaon plus missing energy. We find that a sizable portion of the darkon parameter space is still compatible with the experimental data. Since the darkon-Higgs interaction may give rise to considerable enhancement of the Higgs invisible decay mode, the existence of the darkon could lead to the weakening or evasion of some of the restrictions on the Higgs mass in the presence of fourth-generation quarks. In addition, it can affect the flavor-changing decays of these new heavy quarks into a lighter quark and the Higgs boson, as the Higgs may subsequently decay invisibly. Therefore, we also study these flavor-changing neutral transitions involving the darkon, as well as the corresponding top-quark decay $t\ensuremath{\rightarrow}cDD$, some of which may be observable at the Tevatron or LHC and thus provide additional tests for the $\mathrm{SM}4+\mathrm{D}$.