Search for 3rd generation SUSY particles with the ATLAS experiment at the Large Hadron Collider

ATLAS对第三代夸克产生的限制已经对低微调超对称组态的存在设置了严格的限制。然而，如果它们的质量与它们衰变成的粒子的质量之和非常相似，那么目前对这些粒子的敏感度就会明显减弱。在这种情况下，在第三代夸克衰变中发射的b夸克往往非常软，它们的识别变得极其困难。ATLAS对这种压缩场景的敏感性可以通过开发对事件中附加次级顶点的存在敏感的判别式来增强，而不管它们是否可以与喷流相关联。这个项目的目的是定义这个判别式，并将其应用于使用完整的ATLAS Run 2数据集搜索止损和底部。

The ATLAS limits on the production of third generation squarks are already setting tight constraints to the existent of low fine-tuning supersymmetry configurations. However, the sensitivity to such particles is at the moment significant weaker if their mass is very similar to the sum of the masses of the particles they decay into. In this configuration, b-quarks emitted in the third generation squark decays tend to be very soft, and their identification becomes extremely challenging. The ATLAS sensitivity to such compressed scenarios can be enhanced by developing discriminants that are sensitive to the presence of additional secondary vertices in the event, regardless of whether they can be associated to jets. The aim of this project is to define this discriminant and apply it to searches of stops and sbottoms using the full ATLAS Run 2 dataset.