A radion in a scenario with a warped extra dimension can be lighter than the Higgs boson, even if the Kaluza-Klein excitation modes of the graviton turn out to be in the multi-TeV region. The discovery of such a light radion would be gateway to new p
hysics. We show how the two-photon mode of decay can enable us to probe a radion in the mass range 60 - 110 GeV. We take into account the diphoton background, including fragmentation effects, and include cuts designed to suppress the background to the maximum possible extent. Our conclusion is that, with an integrated luminosity of 3000 $rm fb^{-1}$ or less, the next run of the Large Hadron Collider should be able to detect a radion in this mass range, with a significance of 5 standard deviations or more.
The quest to know the structure of matter has resulted in various theoretical speculations wherein additional colored fermions are postulated. Arising either as Kaluza-Klein excitations of ordinary quarks, or as excited states in scenarios wherein th
e quarks themselves are composites, or even in theories with extended gauge symmetry, the presence of such fermions ($q^*$) can potentially be manifested in $gamma + jet$ final states at the LHC. Using unitarized amplitudes and the CMS setup, we demonstrate that in the initial phase of LHC operation (with an integrated luminosity of $200 pb^{-1}$) one can discover such states for a mass upto 2.0 TeV. The discovery of a $q^*$ with a mass as large as $sim$5 TeV can be acheived for an integrated luminosity of $sim 140 fb^{-1}$. We also comment on the feasibility of mass determination.
