论文标题
Di-higgs生产是一种探究风味变化中性野川耦合的探针
Di-Higgs production as a probe of flavor changing neutral Yukawa couplings
论文作者
论文摘要
顶级合作伙伴在许多新物理模型中都有充分的动力。通常，引入Quarks $ t_ {l，r} $的向量以避免量子异常。探测他们与标准模型颗粒的相互作用至关重要。但是，在当前和将来的实验中，总是很难直接检测到变化的中性耦合。在本文中，我们将展示如何通过Di-Higgs的生产来限制变化的中性Yukawa耦合$ tth $。我们考虑了简化的模型，包括一对量程单元$ t_ {l，r} $。在扰动的单位性和实验约束下，我们选择$ m_t = 400〜 \ mathrm {gev}，s_l = 0.2 $和$ m_t = 800〜 \ mathrm {gev}，s_l = 0.1 $作为基准点。在对数值横截面的幅度分析和评估后，我们发现，由于$（y_ {l，r}^{tt}）^4 $行为，Di-higgs生产的当前约束已经超过了单位性。对于$ m_t = 400〜 \ mathrm {gev} $和$ s_l = 0.2 $，$ \ mathrm {re} y_ {l，r}^{tt} $和$ \ mathrm {imrm {im} y__ {im} y_ {l，r}^{l，r}^{tt { $2σ$ cl。对于$ m_t = 800〜 \ mathrm {gev} $和$ s_l = 0.1 $，$ \ mathrm {re} y_ {l，r}^{tt} $和$ \ mathrm {im} y__ {im} y_ {im} y_ {l，r}^{l，r}^{l，r}^{tt { $2σ$ cl。异常的三重希格斯耦合$δ_{hhh} $也会影响$ y_ {l，r}^{tt} $的约束。最后，我们发现在某些情况下，在离轴区域中，顶级夸克电动偶极力矩可以给出$ y_ {l，r}^{tt} $的更强界限。
Top partners are well motivated in many new physics models. Usually, vector like quarks $T_{L,R}$ are introduced to avoid the quantum anomaly. It is crucial to probe their interactions with the standard model particles. However, flavor changing neutral couplings are always difficult to detect directly in the current and future experiments. In this paper, we will show how to constrain the flavor changing neutral Yukawa coupling $Tth$ through the di-Higgs production indirectly. We consider the simplified model including a pair of gauge singlet $T_{L,R}$. Under the perturbative unitarity and experimental constraints, we choose $m_T=400~\mathrm{GeV},s_L=0.2$ and $m_T=800~\mathrm{GeV},s_L=0.1$ as benchmark points. After the analysis of amplitude and evaluation of the numerical cross sections, we find that the present constraints from di-Higgs production have already surpassed the unitarity bound because of the $(y_{L,R}^{tT})^4$ behavior. For the case of $m_T=400~\mathrm{GeV}$ and $s_L=0.2$, $\mathrm{Re}y_{L,R}^{tT}$ and $\mathrm{Im}y_{L,R}^{tT}$ can be bounded optimally in the range $(-0.4, 0.4)$ at HL-LHC with $2σ$ CL. For the case of $m_T=800~\mathrm{GeV}$ and $s_L=0.1$, $\mathrm{Re}y_{L,R}^{tT}$ and $\mathrm{Im}y_{L,R}^{tT}$ can be bounded optimally in the range $(-0.5, 0.5)$ at HL-LHC with $2σ$ CL. The anomalous triple Higgs coupling $δ_{hhh}$ can also affect the constraints on $y_{L,R}^{tT}$. Finally, we find that the top quark electric dipole moment can give stronger bounds of $y_{L,R}^{tT}$ in the off-axis regions for some scenarios.
