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arXiv 1709.03490hep-ex
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用ATLAS探测器测量质子-质子碰撞中$Z/γ^{*}\rightarrowττ$在$\sqrt{s}=8$ TeV衰变的$τ$极化

Measurement of $τ$ polarisation in $Z/γ^{*}\rightarrowττ$ decays in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

ATLAS Collaboration

摘要:

本文介绍了在$Z/γ^{*}\rightarrowττ$衰变中产生的$τ$轻子的偏振测量,该测量是用$\sqrt{s}=8$ TeV的质子-质子碰撞数据集进行的,对应于2012年在LHC用ATLAS探测器记录的20.2 fb $^{-1}$的积分光度。$Z/γ^{*}\rightarrowττ$衰变是由强子衰变的$τ$轻子和一个处于末态的带电粒子,以及一个轻子衰变的$τ$轻子重建的。的$τ$极化推断从带电和中性强子在强子$τ$衰变携带的能量的相对分数。在对应于该分析可访问的运动学区域的基准区域中测量偏振。$τ$极化提取的$Z/γ^{*}$质量范围内的66 $ < m_{Z/γ^{*}} < $ 116 GeV的整个相空间被发现是$P_τ =-0.14 \pm 0.02 (\text{stat}) \pm 0.04 (\text{syst})$。这与标准模型预测的$P_τ =-0.1517 \pm 0.0019$,这是从ALPGEN事件发生器接口与PYTHIA 6部分子簇射建模和TAUOLA $τ$衰变库。

英文摘要:

This paper presents a measurement of the polarisation of $τ$ leptons produced in $Z/γ^{*}\rightarrowττ$ decays which is performed with a dataset of proton-proton collisions at $\sqrt{s}=8$ TeV, corresponding to an integrated luminosity of 20.2 fb$^{-1}$ recorded with the ATLAS detector at the LHC in 2012. The $Z/γ^{*}\rightarrowττ$ decays are reconstructed from a hadronically decaying $τ$ lepton with a single charged particle in the final state, accompanied by a $τ$ lepton that decays leptonically. The $τ$ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic $τ$ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The $τ$ polarisation extracted over the full phase space within the $Z/γ^{*}$ mass range of 66$ < m_{Z/γ^{*}} < $ 116 GeV is found to be $P_τ =-0.14 \pm 0.02 (\text{stat}) \pm 0.04 (\text{syst})$. It is in agreement with the Standard Model prediction of $P_τ =-0.1517 \pm 0.0019$, which is obtained from the ALPGEN event generator interfaced with the PYTHIA 6 parton shower modelling and the TAUOLA $τ$ decay library.

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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