Phenomenological signatures of additional scalar bosons at the LHC

We investigate the search prospects for new scalars beyond the standard model at the large hadron collider (LHC). In these studies two real scalars S and $$\chi $$χ have been introduced in a two Higgs-doublet model (2HDM), where S is a portal to dark matter (DM) through its interaction with $$\chi $$χ, a DM candidate and a possible source of missing transverse energy ($$E_\text {T}^\text {miss}$$ETmiss). Previous studies focussed on a heavy scalar H decay mode $$H \rightarrow h\chi \chi $$H→hχχ, which was studied using an effective theory in order to explain a distortion in the Higgs boson (h) transverse momentum spectrum (von Buddenbrock et al. in arXiv:1506.00612 [hep-ph], 2015). In this work, the effective decay is understood more deeply by including a mediator S, and the focus is changed to $$H \rightarrow h S,~SS$$H→hS,SS with $$S \rightarrow \chi \chi $$S→χχ. Phenomenological signatures of all the new scalars in the proposed 2HDM are discussed in the energy regime of the LHC, and their mass bounds have been set accordingly. Additionally, we have performed several analyses with final states including leptons and $$E_\text {T}^\text {miss}$$ETmiss, with $$H \rightarrow 4 W$$H→4W, $$t(t)H \rightarrow 6 W$$t(t)H→6W and $$A \rightarrow ZH$$A→ZH channels, in order to understand the impact these scalars have on current searches.