New signals for singlet Higgs and vector-like quarks at the LHC

We consider an extension of the Standard Model involving a singlet Higgs and down type vector-like quarks in the light of the current LHC Higgs data. For a good range of the parameters of the Higgs potential, and a mass range for the heavy vector-like quark, we find that the singlet heavy Higgs arising from the production and decay of the vector-like quarks give rise to (2b~4t) signal. The subsequent decay of the top quarks to $b W^{+}$ give rise to a final state with six b quarks, two same-sign charged leptons and missing transverse momenta with observable cross-sections at the 14 TeV run of the Large Hadron Collider. The Standard Model background for such a final state is practically negligible.

Search for spin-3/2 quarks at the Large Hadron Collider

We consider the pair production of color triplet spin-3/2 quarks and their subsequent decays at the LHC. This particle, if produced, will most likely decay into top quark and gluon, bottom quark and gluon, or a light quark jet and gluon, depending on the quantum number of the spin-3/2 particle. This would lead to signals with ttbar+jj, bbbar+jj, or 4j in the final states. We present a detailed analysis of the signals and backgrounds at sqrt{s}= 7, 8 and 14 TeV and show the reach for such particles by solving for observable mass values for the spin-3/2 quarks through its decay products.