"Table 46" 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）相关分析：本研究呈现了一项针对顶夸克伴子（top squark）成对直接产生过程的搜寻分析。所用事例需满足至少包含两个轻子（lepton），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；同时需包含被标记为b夸克（b-quark）起源的喷注，以及横向缺失动量（missing transverse momentum）。本次分析采用大型强子对撞机（LHC）上的ATLAS探测器（ATLAS detector）在2012年采集的、质心系能量√s=8 TeV的质子-质子碰撞（proton-proton collision）数据，对应的积分亮度为20.3 fb⁻¹。分析未观测到任何超出标准模型（Standard Model）预期的信号。本研究针对两类模型给出了结果诠释：其一为较重顶夸克伴子态（t₂）直接成对产生，随后通过衰变道t₂→Z t₁衰变至较轻顶夸克伴子态（t₁）的模型；其二为自然规范传递型超对称破缺情景下的t₁顶夸克伴子成对直接产生过程，其中中性微子（neutralino，χ₁⁰）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，G）的模型。