| Summary: | The first run of the Large Hadron Collider (LHC) has been enormously successful in both discovering the Higgs and starting to constrain TeV-scale masses for new colored particles. Both the second and future runs of the LHC will continue to ramp up in both energy and collision rate and a possible 100 TeV proton-proton collider on the horizon would push these boundaries even further. While going to such high energies offers substantial opportunities, operating at the necessary collision rates brings notable challenges with it. In particular, higher luminosities entail increased levels of pileup which contaminate the measurement of hadronic jets and, without mitigation techniques, would partially render many of the advancements in heavy particle tagging ineffective. We present two new algorithm to remove pileup at the algorithmic level, allow jet physics to be minimally impacted by high levels of pileup. Moving onto to exploiting the high collision energy of the LHC, while colored particles are abundantly produced, the same is not true for electroweak particles. We perform a careful study of the discovery reach for electroweakly-interacting neutralino and charginos and show that the LHC is unable to cover much of the interesting parameter space. These types of spectra arise in models such as split supersymmetry and are one of the very few ways to probe these types of scenarios. Finally, if upon completion the LHC sees no new particles, it is widely believed that naturalness would be placed under severe pressure. We explore a mechanism called the twin Higgs mechanism in the context of composite Higgs models and show that it is conceivable that untuned models could remain undiscovered by the LHC. Whatever may or may not be found in the second run of the LHC, we show some scenarios under a new collider is needed and the model building one must do to maintain naturalness even after the strongest LHC limits.
|
|---|
