Phenomenology at a future 100 TeV hadron collider

Abstract

Run 1 of the Large Hadron Collider (LHC) has been one of the most successful experiments in particle physics. We are now approaching the end of LHC Run 2, and whether we will discover new physics or not, the high energy particle physics community is already inspecting various possibilities for the future generation of colliders. One of the most intriguing scenarios deals with the exploration of energies so far not reached, with energy scales up to several TeVs, as for example a $\sqrt{s} = 100 $ TeV hadron-hadron collider. This thesis inspects the phenomenological potential of such a machine from two different viewpoints. First, the perturbative Quantum Chromodynamics (QCD) perspective. Monte Carlo event generators play an essential role for data analysis and interpretation at the LHC, and they are vital for exploring the potential of future machines. We aim at improving our current perturbative QCD descriptions with precise predictions through resummation methods. These represent all-orders analytical results which properly account for divergences appearing in the calculations, as those related to the emission of soft gluons. We discuss the automation of soft-gluon resummation within the \Sherpa Monte Carlo event generator framework. We present comparisons between resummed and parton-showered predictions, thereby inspecting which are the necessary steps to be taken in passing from Monte Carlo simulations at the LHC to a Future Circular Collider. In the second part of the thesis we discuss the phenomenology related to Vector Boson Scattering at $\sqrt{s} = 100 $ TeV in a Composite Higgs model scenario, based on the coset $SU(4)/Sp(4)$. We predict limits for the appearance of resonant and non-resonant excesses in the production channel $pp\to ZZjj$. This process provides one of the most interesting possibilities for finding deviations from the Standard Model at a Future Circular Collider.