"Table 1" of "Measurement of the $k_\mathrm{t}$ splitting scales in $Z \to \ell\ell$ events in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector"
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CERN-LHC. A measurement of the splitting scales occuring in the $k_\mathrm{t}$ jet-clustering algorithm is presented for final states containing a $Z$ boson. The measurement is done using 20.2 fb${}^{-1}$ of proton--proton collision data collected at a centre-of-mass energy of $\sqrt{s} = 8$ TeV by the ATLAS experiment at the LHC in 2012. The measurement is based on charged-particle track information, which is measured with excellent precision in the $p_\mathrm{T}$ region relevant for the transition between the perturbative and the non-perturbative regimes. The data distributions are corrected for detector effects, and are found to deviate from state-of-the-art predictions in various regions of the observables. Primary measurement using only charged particles: - Exactly 2 opposite-sign same-flavour dressed leptons (electrons or muons dressed with photons within deltaR < 0.1) - pT(lepton)>25 GeV - |eta(muons)|<2.4 - |eta(electrons)|<2.47 and not within 1.37 400 MeV and |eta(track)|<2.5, excluding dressed leptons - pass charged particles into kT algorithm using R=0.4 or R=1.0 Extrapolation to complete fiducial phase space using charged and neutral particles: - same as before, but use all particles (charged and neutral) with pT(track) > 400 MeV and |eta(track)|<2.5, excluding dressed leptons - pass charged particles into kT algorithm using R=0.4 or R=1.0
欧洲核子研究中心大型强子对撞机（CERN-LHC）。本工作针对包含Z玻色子（Z boson）的末态，给出了k_t喷注聚类算法（k_t jet-clustering algorithm）中发生的劈裂尺度的测量结果。本次测量使用LHC上ATLAS实验于2012年采集的、质心系能量为√s=8 TeV的质子-质子碰撞数据集，积分亮度为20.2 fb⁻¹。测量基于带电粒子径迹信息，该信息在微扰与非微扰区域过渡相关的横向动量（p_T）区间内拥有极高的测量精度。已对数据分布进行探测器效应校正，结果显示其在可观测量的多个区间内与当前主流理论预言存在偏差。 仅使用带电粒子的基准测量： - 严格选取2个异号同味修饰轻子（即ΔR<0.1范围内与光子耦合的电子或μ子） - 轻子横向动量p_T>25 GeV - μ子赝快度|η|<2.4 - 电子赝快度|η|<2.47，且不处于1.37至400 MeV区间，带电粒子径迹赝快度|η|<2.5，且已排除修饰轻子 - 将带电粒子输入至k_t喷注聚类算法，参数R取0.4或1.0 使用带电与中性粒子外推至完整fiducial相空间（fiducial phase space）： - 选取标准与基准测量一致，但需使用所有粒子（带电及中性粒子），要求粒子横向动量p_T>400 MeV，径迹赝快度|η|<2.5，且排除修饰轻子 - 将带电粒子输入至k_t喷注聚类算法，参数R取0.4或1.0
