"Table 25" of "Search for direct top squark pair production in events with a Z boson, b-jets and missing transverse momentum in sqrt(s)=8 TeV pp collisions with the ATLAS detector"

CERN-LHC. A search is presented for direct top squark pair production using events with at least two leptons including a same-flavour opposite-sign pair with invariant mass consistent with the Z boson mass, jets tagged as originating from b-quarks and missing transverse momentum. The analysis is performed with proton-proton collision data at sqrt(s) = 8 TeV collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20.3 fb^-1. No excess beyond the Standard Model expectation is observed. Interpretations of the results are provided in models based on the direct pair production of the heavier top squark state (t2) followed by the decay to the lighter top squark state (t1) via t2 --> Z t1, and for t1 pair production in natural gauge-mediated supersymmetry breaking scenarios where the neutralino (chi1^0) is the next-to-lightest supersymmetric particle and decays producing a Z boson and a gravitino (G) via the chi1^0 --> Z G process.CERN-LHC实验：本研究报告了针对顶超对称夸克（top squark）成对直接产生过程的搜寻分析，分析对象包含至少两个轻子（lepton）的事例，其中存在一对同味异号轻子对，其不变质量与Z玻色子（Z boson）质量相符，同时包含被标记为起源于b夸克（b quark）的喷注以及横向缺失动量（missing transverse momentum）。本次分析使用LHC上ATLAS探测器（ATLAS detector）于2012年采集的质子-质子碰撞数据，该数据的质心系能量为√s=8 TeV，对应积分亮度为20.3 fb⁻¹。未观测到超出标准模型（Standard Model）预期的信号超额。本结果针对两类模型给出解释：一类基于重质量顶超对称夸克态（t2）的成对直接产生，随后通过t2→Z t1的衰变过程转化为轻质量顶超对称夸克态（t1）；另一类针对自然规范传递型超对称破缺（gauge-mediated supersymmetry breaking）场景下的t1成对产生过程，该场景中中性微子（χ₁⁰）为次轻量级超对称粒子，通过χ₁⁰→Z G的衰变过程产生Z玻色子与引力微子（G）。