Exotic heavy particles in four-top final states

To set the scene, we first take a review of the current research status at the Large Hadron Collider (LHC). The most important discovery at the LHC has been that of the Higgs boson in 2012. Investigating the nature of electroweak symmetry breaking in the Standard Model and searching for phenomena beyond the Standard Model are two cornerstones of the research programme carried out by the large experiments at the LHC, ATLAS being one of them.

There are countless possibilities for new phenomena to manifest. Among the most interesting hypotheses, the large Yukawa coupling of the top quark – the heaviest elementary particle – to the Higgs field provides a guiding candle to search for new phenomena.

Reference [1], chapters 1-2 provides a useful overview of the research status at the LHC. Several theories describing phenomena beyond the Standard Model postulate new heavy particles. These particles resemble the well-known Z bosons mediating the weak interaction and therefore are referred to as Z' bosons.

As there are various theories describing Z' bosons, we will take a different approach and focus on a so-called simplified model. This model encapsules the minimum amount of assumptions about a hypothetical Z' boson and would require additional postulates to provide a full account of the story. Nevertheless, it provides a useful description of how it would look like in the detector if such a heavy resonance is produced. Therefore, we will use the top-philic Z' resonance model described in Refs.[2-3] as our benchmark for studying the reconstruction of heavy resonances.

Literature

1. Particle Physics and Cosmology | Pascal Pralavorio | arXiv:1311.1769

2. Probing TeV scale Top-Philic Resonances with Boosted Top-Tagging at the High Luminosity LHC | by Jeong Han Kim, Kyoungchul Kong, Seung J. Lee, and Gopolang Mohlabeng | arXiv:1604.07421v2 | DOI: 10.1103/physrevd.94.035023

3. Model-Independent Production of a Top-Philic Resonance at the LHC | by Nicolas Greiner, Kyoungchul Kong, Jong-Chul Park, Seong Chan Park, and Jan-Christopher Winter | arXiv: 1410.6099 | DOI: 10.1007/jhep04(2015)029