"Table 55" 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.

欧洲核子研究中心大型强子对撞机（CERN-LHC）相关研究：本研究报告了顶超对称夸克（top squark）直接成对产生过程的搜寻结果，分析样本包含至少两个轻子的事件，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b夸克（b-quark）起源的喷注与横向缺失动量（missing transverse momentum）。本分析采用2012年大型强子对撞机（LHC）上的ATLAS探测器采集的质心系能量√s=8 TeV的质子-质子碰撞数据，对应的积分亮度为20.3 fb⁻¹。未观测到超出标准模型（Standard Model）预期的信号过量。本结果针对两类超对称模型给出解读：其一为较重顶超夸克态（t₂）的直接成对产生，随后通过t₂→Z t₁衰变模式衰变为较轻顶超夸克态（t₁）；其二为自然规范媒介超对称破缺场景下的t₁成对产生过程，其中中性伴子（neutralino，χ₁⁰）为次轻超对称粒子，通过χ₁⁰→Z G过程衰变产生Z玻色子与引力伴子（gravitino，G）。