Testing origin of neutrino masses at the CERN Large Hadron Collider

Evidence for neutrino masses clearly indicates the need for new physics beyond standard model. In the last decades, there have also been enomounus experimental efforts to measure neutrino properties and test its generation mechanism. In this thesis, we demonstrate how to test the origin of neutrino mass at the Large Hadron Collider. The proposal consists of two parts: (i) to test a triplet model through exotic Higgs search; (ii) exotic decay of Top quark into GeV Majorana neutrino states. The triplet model predicts the existence of doubly charged Higgs H++ and its decay into same sign dileptons H++ → ℓ +ℓ+. One can look for clean signals of lepton number violation in the decays of doubly charged (H±± ) and singly charged (H±) scalars and by measuring the decay BR of different channels to distinguish spectrum for the light neutrino masses and the unknown Majorana phases. H ±± should be observable at the LHC with 300 fb -1 integrated luminosity in the leptoic channel upto the mass range of 1 TeV. For the second part, we explore top decay into Majorana N. The unique signal final state which consists of same sign dilepton with no significant ET makes the discovery possible. For 100 fb-1 integrated luminosity at LHC, one can probe the BR(W ± → ℓ± N → ℓ ±ℓ±(W∓ )*) as low as 10-4.