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arXiv 2012.09209hep-ph
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味道改变顶部衰变到魅力和希格斯与$ττ$在LHC

Flavor changing top decays to charm and Higgs with $ττ$ at the LHC

Phillip Gutierrez, Rishabh Jain, Chung Kao

摘要:

研究了在CERN大型强子对撞机(LHC)上发现顶夸克衰变为粲夸克和希格斯玻色子($t \to c h^0$)的前景。采用一般的双Higgs模型研究了变味中性Higgs相互作用(FCNH)。我们用\textsc{Pythia} ~8和\textsc{Delphes}进行了部分子水平分析和蒙特卡罗模拟,研究了顶夸克衰变$t \to c h^0$,Higgs衰变为$τ^+ τ^-$,另一个顶夸克衰变为底夸克($b$)和两个光喷注($t\to bW\to bjj$)的变味过程.为了减少希格斯信号的物理背景,只使用τ轻子的轻子衰变,即$τ^+τ^- \to e^\pmμ^\mp +\slashed{E}_T$,其中$\slashed{E}_T$代表中微子中丢失的横向能量。为了重建Higgs玻色子和顶夸克的质量,并有效地去除物理背景,共线近似的高助推τ衰变。我们的分析表明,在$\sqrt{s} = 27$ TeV的高能量LHC将能够发现这个FCNH信号与集成光度$\mathcal{L} = 3$ ab $^{-1}$的分支部分${\cal B}(t \to ch^0) \agt 1.4 \times 10^{-4}$,对应于FCNH耦合$|λ_{tch}| \agt 0.023$。该FCNH偶联显著低于当前ATLAS组合上限$|λ_{tch}| = 0.064$。

英文摘要:

We investigate the prospects of discovering the top quark decay into a charm quark and a Higgs boson ($t \to c h^0$) in top quark pair production at the CERN Large Hadron Collider (LHC). A general two Higgs doublet model is adopted to study flavor changing neutral Higgs (FCNH) interactions. We perform a parton level analysis as well as Monte Carlo simulations using \textsc{Pythia}~8 and \textsc{Delphes} to study the flavor changing top quark decay $t \to c h^0$, followed by the Higgs decaying into $τ^+ τ^-$, with the other top quark decaying to a bottom quark ($b$) and two light jets ($t\to bW\to bjj$). To reduce the physics background to the Higgs signal, only the leptonic decays of tau leptons are used, $τ^+τ^- \to e^\pmμ^\mp +\slashed{E}_T$, where $\slashed{E}_T$ represents the missing transverse energy from the neutrinos. In order to reconstruct the Higgs boson and top quark masses as well as to effectively remove the physics background, the collinear approximation for the highly boosted tau decays is employed. Our analysis suggests that a high energy LHC at $\sqrt{s} = 27$ TeV will be able to discover this FCNH signal with an integrated luminosity $\mathcal{L} = 3$ ab$^{-1}$ for a branching fraction ${\cal B}(t \to ch^0) \agt 1.4 \times 10^{-4}$ that corresponds to a FCNH coupling $|λ_{tch}| \agt 0.023$. This FCNH coupling is significantly below the current ATLAS combined upper limit of $|λ_{tch}| = 0.064$.

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。

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