A study of Higgs search in ATLAS experiment by using a decay mode of H→ττ

我们与川越（科比大学）合作，在大型强子对撞机的ATLAS实验中研究了H→ττ模的搜索问题。和Takemoto（东京大学）与野尻（京都大学）进行了磋商。和其他理论家。我们对标准模型和超对称模型预言的轻质量（100-150 GeV）中性Higgs粒子进行了研究，特别是对WW/ZZ聚变反应产生的非标准模型Higgs粒子进行了研究。关于τ衰变的重建，研究了两种分析方法：双轻子模型和强子-轻子模型。在双轻子模中，来自Higgs的两个τ轻子都衰变到轻子模，在强子-轻子模中，τ轻子之一衰变到强子模，如τ→π v。通过对H→ττ的漂白率、探测器的接收率和分析效率的深入研究，我们得到了在积分光度为30 pb^时，重建的Higgs事例和背景事例数目的预期值<-1>。结果表明，这两种分析模式都有足够的能力发现轻质量的希格斯粒子。为了继续我们的研究，有必要对背景事件进行进一步的调查。

We have studied search for H→ττmodes at ATLAS experiment in Large Hadron Collider in collaboration with Kawagoe (Kobe Univ.) and Takemoto(Tokyo Univ.) having consultation with Nojiri(Kyoto Univ.) and other theorists. We have studied on neutral Higgs with light mass (100-150 GeV) , which is predicted by the Standard Model and or SUSY models.Especially, we focused on fee Standard Model Higgs produced by WW/ZZ fusion reactions. Concerning to the reconstruction of the τ decay, two analysis methods have been investigated : di-lepton mode and hadron-lepton mode. In di-lepton mode, both τ leptons from Higgs decay into leptonic mode, In hadron-lepton mode, one of τ lepton decays in to hadronic mode such as τ→πvSimulations on our computing environment have been performed by using PYTHIA event generator and ATLFAST detector (fast) simulator. After intensive study on blanching ration of H→ττ, acceptance of the detector and efficiency of analysis, we have obtained expectations on number of reconstructed Higgs events together with background events for integrated luminosity of 30 pb^<-1>. As a result, we have found that both two analysis modes have enough capability of discovering Higgs particles with light mass. Further investigation on background events is necessary to proceed with our study.