Discovery Mass Reach for Excited Quarks at Hadron Colliders
  If quarks are composite particles then excited states are expected. We estimate the discovery mass reach as a function of integrated luminosity for excited quarks decaying to dijets at the Tevatron, LHC, and a Very Large Hadron Collider (VLHC). At the Tevatron the mass reach is 0.94 TeV for Run II (2 fb^-1) and 1.1 TeV for TeV33 (30 fb^-1). At the LHC the mass reach is 6.3 TeV for 100 fb^-1. At a VLHC with a center of mass energy, sqrt(s), of 50 TeV (200 TeV) the mass reach is 25 TeV (78 TeV) for an integrated luminosity of 10^4 fb^-1. However, an excited quark with a mass of 25 TeV would be discovered at a hadron collider with sqrt(s)=100 TeV and an integrated luminosity of 13 fb^-1, illustrating a physics example where a factor of 2 in machine energy is worth a factor of 1000 in luminosity. 
Robert M. Harris (Fermilab)