arXiv 1502.008552015-02hep-phhep-ex

多重Higgs偶态场模型中的疏光$Z'$

Leptophobic $Z'$ in Models with Multiple Higgs Doublet Fields

Cheng-Wei Chiang, Takaaki Nomura, Kei Yagyu

备注：: 26 pages, 22 figures, additional discussions and references are added, figures and Tables are modified

摘要：

本文研究了$N$ -Higgs双重场模型中由额外的$U(1)'$规范对称性产生的疏轻子$Z'$玻色子的对撞机现象。我们假设树水平的$Z'$玻色子（i）没有$Z$-$Z'$混合，（ii）没有与带电轻子的相互作用，（iii）没有改变味道的中性流。在这样的设置下，它表明，在$N=1$的情况下，所有的$U(1)'$收费的左手夸克偶和右手的上，下型夸克需要是相同的，而在$N \ge 3$的情况下，可以采取不同的收费为三种类型的夸克。$N=2$案例在上述三个要求下没有很好的定义。我们在LHC上研究了$Z$和$W^\pm$轻子衰变的$pp\to Z'V\to b\bar{b}V$过程（$V=γ,~Z$和$W^\pm$）。对$U(1)'$规范耦合常数最有希望的发现通道或最严格的约束来自于低于$t\bar{t}$阈值的$Z'γ$过程和高于阈值的$t\bar{t}$过程。假设碰撞能量为8 TeV，积分光度为19.6 fb $^{-1}$，我们发现，在低质量区的$Z'γ$搜索的约束可以比从UA 2实验。在$N \ge 3$的情况下，我们考虑四个基准点的$Z'$与夸克的耦合。值得注意的是，如果发现了这样的$Z'$，仔细比较$Z'γ$和$Z'W$信号对于揭示$Z'$与夸克耦合的性质至关重要。我们还提出了在$N=1$和$N\geq 3$的情况下，在14 TeV的大型强子对撞机的$Z'$玻色子的发现范围。

英文摘要：

We study the collider phenomenology of the leptophobic $Z'$ boson from an extra $U(1)'$ gauge symmetry in models with $N$-Higgs doublet fields. We assume that the $Z'$ boson at tree level has (i) no $Z$-$Z'$ mixing, (ii) no interaction with charged leptons, and (iii) no flavour-changing neutral current. Under such a setup, it is shown that in the $N=1$ case, all the $U(1)'$ charges of left-handed quark doublets and right-handed up- and down-type quarks are required to be the same, while in the $N \ge 3$ case one can take different charges for the three types of quarks. The $N=2$ case is not well-defined under the above three requirements. We study the $pp\to Z'V\to b\bar{b}V$ processes ($V=γ,~Z$ and $W^\pm$) with the leptonic decays of $Z$ and $W^\pm$ at the LHC. The most promising discovery channel or the most stringent constraint on the $U(1)'$ gauge coupling constant comes from the $Z'γ$ process below the $t\bar{t}$ threshold and from the $t\bar{t}$ process above the threshold. Assuming the collision energy of 8 TeV and the integrated luminosity of 19.6 fb$^{-1}$, we find that the constraint from the $Z'γ$ search in the lower mass regime can be stronger than that from the UA2 experiment. In the $N \ge 3$ case, we consider four benchmark points for the $Z'$ couplings with quarks. It is noted that if such a $Z'$ is discovered, a careful comparison between the $Z'γ$ and $Z'W$ signals is crucial to reveal the nature of $Z'$ couplings with quarks. We also present the discovery reach of the $Z'$ boson at the 14-TeV LHC in both $N=1$ and $N\geq 3$ cases.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文