Search for nonpointing and delayed photons in the diphoton and missing transverse momentum final state in 8 TeV p p collisions at the LHC using the ATLAS detector
Search for nonpointing and delayed photons in the diphoton and missing transverse momentum final state in 8 TeV p p collisions at the LHC using the ATLAS detector
复制标题
使用 ATLAS 探测器在 LHC 的 8 TeV p p 碰撞中搜索双光子中的非指向和延迟光子以及缺失的横向动量最终状态
DOI：
10.1103/physrevd.90.112005
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发表时间：
2014
影响因子：
5
通讯作者：
Aad G
中科院分区：
文献类型：
--
作者：
Aad G
利用2012年LHC上的ATLAS探测器收集的8 TeV质子-质子碰撞的完整数据样本，科学家们进行了一项搜索，以寻找由于中性长寿命粒子衰变为光子和不可见粒子而产生的偏移顶点的光子。该分析研究了双光子加上缺失横动量的最终态，因此对长寿命粒子的对产生最为敏感。这种分析技术利用ATLAS电磁量热计的能力，对光子的飞行方向和飞行时间进行精确测量。没有观测到超出标准模型对背景的预测。排除限制是在规范介导的超对称破缺模型的背景下设定的，其中最轻的中和子是次轻的超对称粒子，并衰变成光子和引力子，其寿命范围从250 ps到约100 ns。
A search has been performed, using the fulldata sample of 8 TeV proton-proton collisions collected in 2012 with the ATLAS detector at the LHC, for photons originating from a displaced vertex due to the decay of a neutral long-lived particle into a photon and an invisible particle. The analysis investigates the diphoton plus missing transverse momentum final state, and is therefore most sensitive to pair production of long-lived particles. The analysis technique exploits the capabilities of the ATLAS electromagnetic calorimeter to make precise measurements of the flight direction, as well as the time of flight, of photons. No excess is observed over the Standard Model predictions for background. Exclusion limits are set within the context of gauge mediated supersymmetry breaking models, with the lightest neutralino being the next-to-lightest supersymmetric particle and decaying into a photon and gravitino with a lifetime in the range from 250 ps to about 100 ns.