标题： 在LHC上使用多b-喷注通道寻找顶夸克伙伴 显示英文标题

标题： Search for the Top Partner at the LHC using Multi-b-Jet Channels

摘要： 在超越标准模型（SM）的TeV尺度的新物理模型中引入了类矢量夸克。 我们特别考虑该夸克在SU(2)$_L$ (SU(3)$_c$) 规范群下为单态（三态），并且仅与SM的第三代夸克耦合。 这种类型的矢量夸克通常被称为顶夸克伙伴。 顶夸克伙伴$t_p$会衰变为$bW, tZ$ 和$th$。 在ATLAS和CMS合作中，顶伙伴已在$bW$和$tZ$的最终状态中被搜索，而基于$t_p\to th$衰变模式的搜索尚未开始。 然而，衰变为$th$非常重要，因为如果在TeV尺度存在某种强动力学，该衰变模式将显著增强。 在存在轻希格斯玻色子的情况下，衰变模式$t_p\to th$随后发生$h\to b\bar{b}$会产生三个底夸克。 我们研究了在LHC实验8 TeV运行中使用多b-喷注事件对顶伙伴的敏感性。 多b夸克喷注事件在现有的ATLAS和CMS合作组的$t_p\rightarrow bW$和$tZ$搜索中起到了补充作用。 显示英文摘要

摘要： Vector-like quarks are introduced in various new physics models beyond the standard model (SM) at the TeV scale. We especially consider the case that the quark is singlet (triplet) under the SU(2)$_L$ (SU(3)$_c$) gauge group and couples only to the third generation quarks of the SM. The vector-like quark of this kind is often called a top partner. The top partoner $t_p$ decays into $bW, tZ$ and $th$. In the ATLAS and CMS collaborations, the top partner has been searched in the final states of $bW$ and $tZ$, while the search based on the decay mode $t_p\to th$ has not been started yet. However, the decay into $th$ is important since it is significantly enhanced if some strong dynamics exists in the TeV scale. In the presence of a light higgs boson, the decay mode $t_p\to th$ followed by $h\to b\bar{b}$ produces three bottom quarks. We study the sensitivity for the top partner using multi-b-jet events at the 8 TeV run of the LHC experiment. The multi-b-jet eventss turn out to play a complementary role to the existing $t_p\rightarrow bW$ and $tZ$ searches by the ATLAS and CMS collaborations.