Prospective study of highly boosted Higgs pairs decaying to four b quarks

The production of pairs of Higgs bosons is a key benchmark process for future colliders because it provides crucial insight into the Electroweak Symmetry Breaking mechanism but it is probably out of the current reach of the Large Hadron Collider. CERN is currently leading a study that analyzes the feasibility of a 100 km circular collider located in the Geneva area. The hadronic Future Circular Collider (FCC-hh) is expected to work at a center of mass energy of 100 TeV and to collect a total integrated luminosity of O(30) /ab. This thesis describes a Monte Carlo study targeting the search for hh -> bbbb in a boosted kinematic regime, using proton-proton collisions at a center of mass energy of 100 TeV. The focus is on the impact of the granularity of the hadronic calorimeter on the significance for observing hh -> bbbb, targeting detector optimization studies for future colliders. In addition to traditional kinematic variables, jet substructure observables are also explored. For the FCC-hh, the achieved significance is 8.8 ± 1.6 (stat.) for an integrated luminosity of L = 30 /ab, which is above the conventional 5 sigma discovery threshold. When using particle flow jets, the significance changes by approximately 54% over the range of detector configurations considered. The change is more accentuated when using pure calorimeter jets (~71%).