"Table 38" 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。本研究针对直接顶超对称夸克（top squark）的成对产生过程展开搜寻，分析事件需至少包含两个轻子，其中存在一对同味异号轻子对，其不变质量与Z玻色子质量相符，同时需包含被标记为起源于底夸克的喷注以及横向缺失动量。本分析基于大型强子对撞机（LHC）的ATLAS探测器于2012年采集的质心系能量√s=8 TeV的质子-质子对撞数据完成，该数据集的积分亮度为20.3 fb⁻¹。未观测到显著超出标准模型预期的信号。本研究针对两类模型场景给出结果诠释：其一基于较重顶超对称夸克态（t₂）的直接成对产生，随后通过t₂→Z t₁衰变至较轻顶超对称夸克态（t₁）；其二针对自然规范媒介超对称破缺场景中的t₁成对产生过程，该场景中中性微子（neutralino）为次轻超对称粒子，并通过χ₁⁰→Z G过程衰变产生Z玻色子与引力微子（gravitino）。