Search for excited quarks in q q ¯ → γ γ at the CERN LHC

If quarks are composite particles, then excited states are expected to play a role in the Large Hadron Collider phenomena. Concentrating on virtual effects, and using a large part of the compact muon solenoid detection criteria, we present here a realistic examination of their effect in diphoton production at the CERN LHC. For various luminosities, we present the 99% confidence limit (CL) achievable in {lambda}-M{sub q*} parameter space where {lambda} is the compositeness scale and M{sub q*} the mass of the state. For a q* of mass 0.5 TeV, {lambda}{<=}1.55(2.95) can be excluded at 99% CL with 30 (200) fb{sup -1} integrated luminosity.