Search for hbsm double charged scalar bosons in multi-leptons final states using proton-proton collisions at $\sqrt{s}$ = 13 TeV with the atlas detector.

This thesis entails the latest measurements on the Higgs boson production in association with heavy vector bosons i.e. $W$ and $Z$. The experimental signatures with the two leptons together with the same electric charge or multi-lepton final states have been employed in the searches for physics beyond the Standard Model (BSM) at LHC. The various models detect heavy BSM particles yielded during proton-proton collisions and then get decayed into multiple massive SM electroweak gauge bosons or top quarks. The signatures with the two leptons of same charge or three or four leptons with various charge combinations have been exploited by the ATLAS and CMS experiments in order to investigate possible SM extensions and phenomenology. The riveting expansion among the preferred SM extensions is instigating SM sector of the weak gauge triplet of scalar fields along with non-zero vacuum expectation value of the neutral component that leads to the neutrino masses through the type-II seesaw mechanism. The phenomenology of the doubly charged scalar bosons ($H^{\pm\pm}$) that can be produced in pairs and then decay into W bosons with the same charge and singly charged scalar bosons ($H^{\pm}$) decay into W along with Z bosons are taken in consideration.